The Dragon Ball franchise is about Goku, plain and simple. The series is the story of a monkey-tailed boy who grows up to be the world's greatest warrior. He makes friends along the way who become secondary characters, but at the end of the day, Dragon Ball is still Goku's story.
Even as other characters gained popularity and more interesting character arcs, Goku was still front and center in the story, his family standing beside him. As the series has progressed, Goku's family got bigger and bigger, starting with his adoptive grandpa, leading to his wife, his kids, and even his biological father and brother.
As we said, the main focus is still on Goku, which is why some fans might not know everything there is to about Goku's parents, his kids, his in-laws, etc. Who exactly are Goku's biological parents, what does he have in common with his son's father in-law, and why does his second son look exactly like him? These are the kinds of things you have to be a superfan to know.
Since his family has taken center stage for most of, if not all of the Dragon Ball franchise, we decided to bring you 25 Crazy Facts About Goku And His Family.
25 GOKU'S TRUE NAME
Let's start off with the first family member of Goku's we were ever introduced to: his Grandpa Gohan.
Gohan wasn't actually Goku's biological grandpa, but he did adopt him after finding him in the woods as an infant. In fact, it was Grandpa Gohan who gave Goku his Earth name.
On Planet Vegeta, Goku was known as Kakarot, a name that was derived from "carrot," keeping with the theme of Saiyan names being based on vegetables.
Of course, Goku was too young to know his Saiyan name when he was sent to Earth and found by Gohan.
When Gohan stumbled upon the monkey-tailed boy, he decided to call him Goku, a name that comes from the main inspiration of the original Dragon Ball series, Journey to the West. The classic story follows the Monkey King, Sun Wukong, whose name translates to Son Goku in Japanese Kanji. Since Goku was based on the Monkey King, Toriyama gave him this name.
This would come full circle as Goku would go on to name his son after his grandpa; a fitting tribute to the man who adopted him, raised him, taught him to fight, and gave him an Earth name.
24 THE RESEMBLANCE IS UNCANNY
Goku's father was a Saiyan by the name of Bardock, a character that we were introduced to in Bardock: The Father of Goku. From the first appearance of the character, we saw where Goku got his looks from, since he is basically an exact clone of his father. This isn't exactly a secret or anything, you can figure this out just by looking, but there are actually some other interesting facts tied to this family resemblance.
For one thing, Goku's second son, Goten, seemed to inherit the complete clone gene from his father, since he looks just like Goku during his early Dragon Ball days. That signature wild hair makes him look identical to his father and grandfather.
It seems like the "clone gene" is only passed down to the second son in the family, since Raditz was the eldest of Bardock's two sons, and he didn't have the signature hair style.
The same goes for Gohan, who had multiple hairstyles throughout Dragon Ball Z, but never his father's. Strangely enough, this gene seems to be one shared between all lower-class Saiyans, as seen in the character Turles of The Tree of Might, though this aspect of Saiyan biology/society might not be canon.
23 BARDOCK AND GOKU'S SHARED NEMESIS
Goku's father is a pretty interesting character, one with a will as strong as Goku himself. In fact, the two share more than just looks in common. Both faced Frieza at on point in their lives, though Bardock did not survive the encounter.
To get to the final moments of Bardock's life, let's first look at how he got there. Bardock was the leader of a group of low-class Saiyans who were sent by Frieza to planets so that their Great Ape forms could conquer it and add to the tyrant's empire.
However, Frieza soon began to fear the Saiyans' power, they got stronger after every battle and soon one might become powerful enough to overthrow him. Frieza destroyed Planet Vegeta, but before that happened, Bardock made his way through Frieza's army to face the tyrant one on one. Unfortunately, Bardock ended up perishing in the fight, but, in the ultimate irony, his son became the thing that Frieza feared the most: a Saiyan who became strong enough to destroy him.
The fact that both Bardock and Goku faced Frieza takes the term "like father, like son" to a whole new level, creating a deep connection between the father and son who never actually met.
22 BARDOCK'S CAMEO
Interestingly enough, Bardock wasn't actually canon to the manga for quite some time. He was a character created originally for the Father of Goku film and the events that took place, as with most Dragon Ball movies, were not considered to be canon.
Akira Toriyama created the design for Goku's father, but that's about all there was connecting the manga/main anime canon to the Bardock movie. However, the movie doesn't rewrite, invade, or contradict any of the main canon, so by all means this background could be considered the "true" story of the fall of the Saiyans and how Goku got sent to Earth.
In fact, Akira Toriyama loved the character and the way he was depicted so much that he decided to give Bardock a cameo in the Dragon Ball Z manga, which thus placed the film in the canon of the series, since Frieza recognizes Goku as Bardock's son when they first meet.
This cameo was featured in the anime as well, but in the manga made The Father of Goku one of the few films in Dragon Ball history to be considered part of the main canon of the universe, connecting the thread between Goku and his father, if only for a brief moment.
21 GOKU AND SUPERMAN
Fans of both Dragon Ball Z and DC comics have long since compared Goku to Superman. They do have quite a bit in common after all, which is probably why the internet has fought over who would win for decades.
Both characters were sent to Earth from an alien planet that was eventually destroyed, both characters have great strength and powers that other Earthlings do not have, both characters are among the last of their kind, both have an alien name and an Earth name, both became great heroes of Earth, and both of their fathers are rather similar in character - and we're not just talking about their shared taste in headbands.
Superman's father, Jor-El, knew that Krypton was going to explode due to instability, but no one believed him. Similarly, Bardock was the only Saiyan who knew that Frieza planned to annihilate their race and destroy Planet Vegeta.
Both their fathers used what resources they had to send their children away so that they would be safe from the destruction of their planets.
Kal-El was sent to Earth, where he was taken in by the Kents in Kansas, and Goku was sent as an "infiltration baby" to Earth, a means to get him far away that resulted in him also being raised in the countryside by an adoptive family. Though it has never been confirmed, Toriyama could have been inspired by the story of Superman when creating Goku's Saiyan background.
20 THE MYSTERY OF GOKU'S MOM
We've met Goku's dad and know that he's canon, but what do we know about his mother?
Well, for one thing, we know she has never been seen in an anime adaptation of the franchise. Her only appearances have been in some video games and in Jaco the Galactic Patrolman, a manga by Akira Toriyama that takes place in the same universe as Dragon Ball. The manga occasionally crossed over with the lives of Dragon Ball characters, including checking in on planet Vegeta, showing us our first like at Goku's mother, a Saiyan woman by the name of Gine.
Gine has not been introduced in any anime and even her appearance in the Jaco might not be canon, since this was the same series that had a major continuity error in relation to Dragon Ball. Specifically, the manga depicted Goku being much older when he was sent to Earth; old enough to talk. Furthermore, Goku was found wearing his Saiyan armor when Grandpah Gohan encountered him.
So, who knows if this is what Gine was really like, or if that was even really her name. Then again, it did come from Toriyama himself, which does lead us to believe everything we know about her.
19 Gine was a Saiyan who didn't fight
If the Gine that we met in Jaco the Galactic Patrolman is the true, canon version of the character, then it actually tells us a lot about the character. Specifically, it shows us just how much she was like her second son, gentle and kind.
While Goku eventually developed great power and fighting instinct, he kept his kind and gentle nature throughout his life, something that he may have gotten from his mother. See, while Saiyan hierarchy might be based on power levels, they can't all be fighters. There needs to be a labor force.
Because of this, those with a lower battle power and/or lack of battle instinct do menial labor for Planet Vegeta. Gine was one of these Saiyans, a gentle soul who, though stronger than an average human, did not have a high power level or the desire to fight others. Thus, she ended up finding employment in meat distribution, which, at the end of the day, is still an important task, since Saiyans do love to eat. 3
Gine's gentle nature ended up being passed down to Goku - in a way. When Grandpa Gohan first found baby Kakarot, he was rowdy and aggressive, only calming down after a head injury knocked out his Saiyan instinct.
18 BARDOCK AND GINE'S UNUSUAL RELATIONSHIP
As a gentle, kind, and rather low-powered Saiyan, Gine was a bit of an outlier amongst Saiyan culture, but that's not the only thing that seperated her from the rest of her people.
Gine's gentle, kind nature and Bardock's noble ways lead the two to form a relationship that was unlike any other on the planet.
See, in Saiyan culture, men and women only choose mates for breeding purposes. Their relationship seeming to only last as long as needed in order for the race to continue to surviving.
Furthermore, the Saiyans also seemed to have access to technology that bypassed certain aspects of birth, but we don't know anything for sure. What we do know however, based on Jaco the Galactic Patrolman, is that Gine and Bardock were a rare case of mates who were in a real relationship, actually getting married and staying together for love rather than reproductive purposes.
This, in turn, is another connection to the House of El, since some interpretations depict Superman's alien parents as one of the only loving relationships on Krypton. Comic connections aside, it's incredibly sweet that Bardock and Gine were in love when the rest of their race barely knew the meaning of the word.
17 FAMILY REUNION FROM BEYOND THE GRAVE
When Planet Vegeta was destroyed and Gine and Bardock were eliminated, both Raditz and Goku were off-planet, which is how they survived. Raditz was on an assignment to conquer a planet for Frieza and Goku was sent to Earth.
Goku was sent to Earth under the guise that he would infiltrate the planet and eventually prime it to be taken over by Frieza. However, while this might have still been Goku's "mission," it might have also been a way to get him off-world and safe from the coming destruction of the Saiyan race.
Either way, Bardock and Gine never really got to see their kids grow up, nor did they ever get to "meet" Kakarot, since a lot of Saiyan's infant life is spent away from their parents from what we have seen.
Regardless of what Jaco might tell us about Goku's age before he was sent off, the fact remains that Gine and Bardock didn't get to see much of their kids before their demise, save for when the two met Goku in a storyline of Dragon Ball Fusions. However, it was a bittersweet reunion, since both Bardock and Gine found it best to hide who they were, with Goku remaining oblivious to their identities during their interactions.
16 Bardock, Goku, Goten, and Gohan are all voiced by the same woman
Many fans of Dragon Ball Z in America know Sean Schemmel to be the voice of Goku - a role that he's had for over 20 years. However, in Japan, voice actress Masako Nozawa has provided the character's voice for even longer, going all the way back to the original Dragon Ball series.
Even more impressively, Masako Nozawa also provides the voice for nearly every male member of Goku's family. Nozawa voices Goku, his father Bardock, and both of his sons, Goten and Gohan. It's not enough that every member of this family looks identical, they also sound the exact same!
Well, save for Raditz, who is the only male member of Goku's family not voiced by Masako Nozawa, The reason for this has never been stated, though perhaps it would have just been too confusing.
Another interesting fact about the Son boys' voices is that, while it's not quite as impressive or wide-spread as the Japanese version of the series, there is also a shared voice actor between Goku and his son in the English version. In some versions of the dub, the voice of Gohan from the beginning of Z through the end of the Cell Saga, Stephanie Nadolny, also provided the voice for young Goku in both the later dub of the original Dragon Ball and when he was turned into a kid in Dragon Ball GT.
15 COUSIN CELL
Dr. Gero was a brilliant scientist, creating a series of Androids for the Red Ribbon army meant to take revenge on Goku. Androids 16-18 were impressive enough, haivng infinite energy from an internal power source, and the latter two were some of the first and only successful cases of humans being turned into cyborgs. Even more impressive was his greatest creation, the one and only bio-android in the Dragon Ball franchise - aside from Androids 21, who appears in Dragon Ball FighterZ - Cell.
Cell, as his name implies, was created using the cells of the world's greatest fighters, their DNA providing him with great powers and abilities. This made him one of the strongest beings in the world before his defeat. Cell's DNA make-up is comprised of the DNA of Piccolo, Frieza, King Cold, Krillin, Vegeta, Goku, and Gohan. What does all this have to do with Goku's family?
Since Cell has some of both Goku and Gohan's DNA, it means that he is, in some way, related to them - making him a cousin of sorts to the Son family.
It's a good thing he was defeated, though, since we can't really imagine Goku and Cell getting along at a family reunion!
14 RADITZ'S REVEAL
This is something that all Dragon Ball Z fans knew at some point, but may have forgotten about as the series unfolded. Throughout all of Dragon Ball, there was no implication that Goku was an alien - just a strange child with super strength and a monkey tail. Heck, even when Goku turned into a giant ape monster during a full moon, no one really wondered if it was because he was an alien, since the original Dragon Ball series had a bit more fantasy to it, and very little sci-fi.
With the first episode of Dragon Ball Z came a reveal that would forever change the course of the franchise.
That reveal was, of course, that Goku was a Saiyan from the planet Vegeta. He was sent there to destroy the planet and prime it for being conquered, but a bump on his head caused him to lose his Saiyan battle instincts. We also learned that the rest of the Saiyan race was gone, save for a few survivors.
Who told Goku all of this? It's wasn't Vegeta or Nappa - no, it was Goku's own brother, Raditz, who told us everything we needed to know about the Saiyans, their race, and their power.
13 GOKU TURNED HIS BACK ON RADITZ
There are a lot of tropes and staples of the Dragon Ball franchise; training montages, surpassing limits, hiding true power, etc., but, perhaps the most prevalent of them all lies in how the villains are treated.
The villains of Dragon Ball are known for getting second chances, often being spared by Goku himself so that they can one day change their ways and do good for the world. This happened with Yamcha, Piccolo, Buu, Frieza in Super (sort of), and of course, Vegeta, who has arguably the greatest character arc in the entire franchise.
Despite the fact that Goku has a great capacity for forgiveness, even when it comes to some of worst villains in his rogues gallery, his brother never got this treatment. Sure, Raditz was destroed before he could really get a second chance, but other characters have passed and still gotten to come back as an ally and friend of Goku's.
Not that there's anything wrong with Goku's choice - Raditz was pretty evil - but other, more evil villains have been forgiven for much worse things than the minor acts of evil that Raditz committed.
It's actually kind of sad that Goku couldn't even forgive his own brother.
The Saiyan race wasn't always a planet full of conquerers. Sure, they were battle-hungry warriors who were always looking for a fight, but they never really seemed to want to expand their empire.
No, this purpose was introduced when Frieza took over Planet Vegeta and enslaved the Saiyan race, turning them into soldiers in his galactic army. Their Great Ape forms served as powerful tools for conquering planets, since a single Saiyan could destroy an entire race in a single day. After Frieza destroyed Planet Vegeta, there were only a few Saiyans left in the universe, and the galactic tyrant himself didn't even know about Goku.
This fact came into play during the Namek Saga, when Frieza met Gohan before he met Goku. Upon seeing this child, he recognized him as a Saiyan, and because he didn't actually know who Goku was, the only Saiyan he knew who had any sort of resemblance to this child was, of course, Raditz.
Yes, for those who don't remember, Frieza mistook Gohan to be Raditz's son, both because he had not known about Goku and because he wasn't aware of Raditz' passing. This mix-up could also be attributed to Frieza looking down on the Saiyan race, and not really caring to differentiate between them, but that's a whole other issue.
11 GOKU AGREED TO MARRY CHI-CHI BECAUSE HE WAS HUNGRY
Goku and Chi-Chi aren't your typical married couple. In fact, you could broaden that to the fact that they aren't very typical as people, either.
Chi-Chi was the warrior daughter of the Ox-King, a mountain of a man who ruled over an actual mountain. She herself spent her younger years fighting and running from monsters while wearing a helmet with a blade and laser on it, which is anything but normal. Then there's Goku, who is, as we all know, an alien who was sent to earth to destroy it, but after getting hit on his head and being raised by a kind old man, he became a noble martial artist.
In fact, Goku's upbringing in the woods, and the eventual passing of his Grandpa, left him a bit naive in the ways of the world. Because of his lack of understanding of most aspects of society, Goku agreed to marry Chi-Chi when they were both very young.
The reason for this is that Goku thought a wedding was some kind of food and, being the big eater that he is, he agreed to marry Chi-Chi, forgetting his promise until she reminded him many years later. Well, they do say that the way to a man's heart is through his stomach.
10 GOKU IS SCARED OF HIS WIFE
Goku is pretty powerful. It's not all that far-fetched to say that he is the strongest mortal warrior in his Universe, and even if he isn't, he's pretty dang close. Suffice it to say, with how much power Goku has, there shouldn't really be anything that he's afraid of - maybe except for losing his loved ones, but even then he has the power to protect them in almost any situation. Yet, there is one thing that he does fear, and it comes from his own family. Specifically, he is afraid of his wife.
Yes, the most powerful Saiyan in perhaps the entire history of the galaxy is afraid of his human wife.
Chi-Chi is just an ordinary human, well-versed in martial art, but not in superhuman aspects of fighting. She can't fly, she can't shoot beams out of her hands, and she is nowhere near as strong as her Saiyan husband. And yet, Goku cowers at the very sound of her voice rising.
He runs and hides whenever she is mad and even though he sometimes manages to get away with the things that frustrate or anger Chi-Chi, he is, without a doubt, afraid of her. This sort of makes Chi-Chi one of the strongest characters in the franchise, since she has a lot of control over Goku.
9 CHI-CHI HAS FOUGHT EVERY MEMBER OF GOKU'S FAMILY
Speaking of Chi-Chi's strength, she has had a long history of practicing basic (that is non-superhuman) martial arts. She was trained by her father and used her fighting skills to protect herself as a child, even going on to compete in the World Martial Arts Tournament, showing complex and masterful skill of certain fighting styles.
Chi-Chi even gave her future husband a run for his money when they reunited at the tournament. In fact, this marked the beginning of a strange trend in Chi-Chi's life: the fact that she has fought every member of her and Goku's family.
Chi-Chi fought Goku at the World Martial Arts Tournament near the end of Dragon Ball, and she later fought her first son in a filler arc of Dragon Ball Z. In the Garlic Jr. saga, Chi-Chi was affected by the Black Water Mist, which caused her to attack Gohan while under its influence. Lastly, at the beginning of the Buu saga, a flashback revealed that Chi-Chi taught Goten everything he knows in terms of basic martial arts, since Goku wasn't around to teach him and Gohan was busy with school.
It's crazy to think that Goku, who loves fighting, has not fought both of his sons, while Chi-Chi, who rather dislikes fighting, has.
8 A ROYAL FAMILY
One of Vegeta's favorite things to do is tell everybody that he's royalty. He constantly refers to himself as the prince of all Saiyans, often using it to exaggerate points, like "how could the prince of Saiyans be surpassed by a lowly peasant" or something along those lines. Here's the thing, Goku is also technically royalty: he just married into it.
You don't see him bragging about it as much as Vegeta, but Goku's marriage to Chi-Chi actually means he also belongs to a royal family.
How does that work? Well, don't forget that Chi-Chi is the daughter of the Ox-King, and though his kingdom is small, only consisting of Fire Mountain, he is still a king all the same, making Chi-Chi a princess. By extension, this makes Goku a prince and their whole family royalty.
Of course, all of the Ox-King's treasures burned down, so they're the prince and princess of jack squat, but the same goes for Prince Vegeta, who only technically "rules over" Goku and maybe his kids. Regardless, because of how far back it was that the Ox-King was actually presented as a king, most Dragon Ball fans might have forgotten that Goku's family is royalty.
7 GOHAN'S NAME
Saiyan's don't seem to be all that creative. Sure, they might be able to think up creative battle strategies, but when it comes to actually using their brains for something besides battle, they kind of stink. It's probably the reason why their planet was named after their royal family, all of whom share the same name, Vegeta.
It might also be the reason that Goku just named his son after his adoptive Grandpa, Gohan - a fact that some people might have forgotten because Dragon Ball was not as popular as Dragon Ball Z.
We are here to remind everyone that Goku's first son is indeed named after his grandpa, and that his name revealed just how uncreative and somewhat uncaring Goku is when it comes to his son. In a flashback during the Cell Saga, we saw that Chi-Chi and her father were struggling to come up with a name for her and Goku's son, while Goku himself remained uninterested in the matter, and his son as well.
When Chi-Chi mentioned Goku's Grandpa, their son lit up and seemed happy about the name, which led them to name him Gohan.
The dark part about this is that Goku didn't seem interested at all in his son until he got to name him after his Grandpa.
6 GOHAN'S TAIL
Saiyan genetics are a bit confusing. We know that the second son of some Saiyans will look much like their fathers, and that hybrids have the potential to be stronger than pure-bloods. What we don't know, however, is how the genetics of their tails work exactly.
See, Gohan was the only half-Saiyan to be seen with a tail, and after it was cut off, the concept of Saiyan tails disappeared from the franchise. What's the reasoning behind this?
Akira Toriyama has stated that Saiyan tails are a recessive trait, which was supposed to be the explanation for the lack of tails on Goten, Trunks, and even Bulla. However, the science of this doesn't really check out. It's not like we're bing sticklers for science in Dragon Ball, but the explanation just seems a bit off.
The more likely explanation is that, after seeing both Goku and Gohan's Great Ape transformations everyone probably agreed that the half-Saiyans' tails should be cut off as early as possible. Thus, Gohan was the only half-Saiyan to ever be seen with a tail in the entirety of the Dragon Ball franchise, which also makes him the only half-Saiyan to turn into a Great Ape.
5 MR. SATAN AND VIDEL JOINED A FAMILY OF CHAMPIONS
Here's a trivia question for all you Dragon Ball fans out there: what do Goku, Gohan, Videl and Mr. Satan all have in common? If your answer was the fact that they have all won tournaments, then you'd be correct.
Since Mr. Satan and Videl are now part of Goku's family though Gohan's marriage to Videl, this means that they are a family of champions. To start, Goku won the 23rd World Martial Arts Tournament, which was the first time the tournament was featured in the franchise.
From there, Gohan went on to win the Cell Games. While not any form of official tournament, it still technically makes him a champion, even if he doesn't have a belt to go with it - though his Great Saiyaman belt does look an awful lot like a champion belt.
His future wife Chi-Chi also won the junior division of the World Martial Arts Tournament, and his future father-in-law won the World Martial Arts tournament quite a few times after Goku stopped entering.
Of course, Mr. Satan ended up taking credit for defeating Cell, which creates its own weird familial issues with Goku and his family, but that's another story for another time.
4 GOHAN WAS MEANT TO REPLACE GOKU
This whole list is based around the fact that, while Goku is the main protagonist of the series, the Dragon Ball franchise has followed his entire family as the story unfolded in Dragon Ball Z. In fact, Goku's son almost took over as the series protagonist.
Obviously, as Goku started to get older, Gohan did too, which made things a bit complicated for storytelling, since Akira Toriyama wasn't sure how to make this middle-aged dad seem interesting as the years passed.
Toriyama's plan was to phase out Goku as the main character and replace him with Gohan.
The evidence of this decision, which was eventually reversed, can be seen at the end of the Cell saga and the beginning of the Buu saga. Gohan was the one who defeated Cell, which is enough to pin him as the new main character, and when Goku decided to stay dead, it really started to look like his son would take over. Finally, at the beginning of the Buu saga, we followed Gohan as he entered high school and fought crime as the Great Saiyaman, his exploits taking center stage before his father finally returned from the dead.
3 GOTEN'S "ORIGINS"
Here's a fun fact: Goten is the youngest Super Saiyan in existence. He was only 7 years old when he first exhibited the ability to go Super. In fact, he may have been younger when he achieved it, since a flashback revealed that the first time he changed was when his mother was teaching him martial arts, which might predate when he went Super in front of Gohan.
Goten was really young when he first went Super Saiyan, and his ability to do so might be attributed to his origins.
Goku didn't meet Goten until the Buu saga, which means that Goten was conceived some time in the resting period before the Cell Games, which Goku and Gohan used to relax their bodies and minds to better prepare for the fight. During this time, Goku and Gohan stayed in their Super Saiyan forms so that their bodies could get used to the energy drain and thus make the form more efficient.
This means that, if Goten was conceived during this time, then Goku was a Super Saiyan, which may be why his second son had access to the form at such a young age. Of course, that's just a theory, but it's funny if true.
2 GRANDPA GOKU
Goku is the only Saiyan grandpa in the franchise. Sure, there's also Bardock, King Vegeta, and the entire history of every male Saiyan in existence, but they're all long gone.
What we're saying is that Goku is the only Saiyan alive who has grandchildren. In fact, he is the only Saiyan to live long enough to see his grandchildren, which is most likely attributed to the fact that he is also the father of the first Saiyan hybrid. However, Goku isn't really the greatest grandpa.
A lot of fans like to joke that Goku is a bad dad and, at times, he can be, but a lot of these jokes tend to focus on the fact that Piccolo trained and took care of his son while he was Goku was in the Underworld. This role seems to have extended to Gohan's daughter, Pan as well since, in Dragon Ball Super it is revealed that Piccolo babysits for his former student quite frequently, and he's actually pretty good at it.
He's definitely way better than Pan's actual grandpa, since he put her in danger, lost her, and still gets all the love from her despite it. Yeah, Goku shouldn't be around kids at all, should he?
1 A FAMILY OF SONS
Throughout this list, we have made brief mention of Goku's full name, which is Son Goku. This name is the Japanese version of Sun Wukong, the Monkey King of Journey to the West that Dragon Ball was initially based on.
In the original Japanese version of the Dragon Ball franchise, and even in some translations of the manga, Goku's full name is referred to quite often, and he is called "Son-Kun" more than he is called "Goku" at times. Yet, in the American version of the franchise, that is, in the dubs, this part of his name is pretty much non existent.
The name comes from his grandpa and extended to his family as their surname. Goten and Gohan's full names are Son Gohan and Son Goten. In most of the English dubs, this is completely absent; there is no mention of Goku's surname.
However, there was one dub that included the "Son" of Goku's name, the Dragon Ball Kai dub of the series. In his speech Freiza after going Super Saiyan, Goku says "I am Son Goku..." and it is pretty much the only time we've heard the character's surname in the English dub of the anime, which is pretty crazy to think about.
Do you have any other trivia to share about Goku's family from Dragon Ball? Let us know in the comments!