The theme of family was always a dominant one in Supernatural, with the bond of friendship a close second. Dean Winchester, despite having his fair share of good and bad traits, managed to forge significant friendships during his time on the show, with these characters becoming a core part of his life.
Since Dean considered Bobby Singer to be his surrogate father, he’s ruled out of being considered a friendly figure. Likewise, characters that were his actual family don’t qualify either, along with those that were mainly romantic interests. Of course, Dean considered all of his friends like family, although some were closer than others.
Kevin Tran
Kevin was thrust into the Winchesters’ lives due to his sudden role as a prophet. However, Dean told Kevin that he had grown into becoming their family, something that brought Kevin to tears and made him love Dean in return.
Although the argument can certainly be made that Kevin might not have been Dean’s true friend due to the latter’s inaction after his death, Kevin did continue to place faith in Dean and even saved his life as a ghost in Season 15.
Claire Novak
Due to their personalities matching, Dean and Claire got along a heck of a lot better than she did with Sam. They were both driven by rage and insecurity, which Dean used to appeal to Claire’s fierce personality and get her to open up to him.
They weren’t so close that Claire didn’t try to shake him off when he tried to be protective of her for Jody’s sake, but if there was one member of Team Free Will who understood Claire’s rebellious streak it had to be Dean.
Garth Fitzgerald IV
Dean usually saw Garth as more of an annoyance than a real buddy, with Garth being oblivious to all this and remaining affectionate to Dean. It did become better later, though, as Dean overlooked his instinct of killing monsters when he let Garth live as a werewolf.
They weren’t as close as Garth was to Sam, seeing as he named his twins after Sam and Castiel rather than giving any tribute to Dean. The interactions these two had were definitely memorable, as Dean couldn’t make heads or tails of Garth’s extreme optimism, which ultimately grew on him.
Rowena MacLeod
It could only be friendship that made Dean overlook all the bad things Rowena had done as a villain. Having started out as enemies, Rowena became the Winchesters’ friend after repeatedly helping them out in their cases and against powerful beings.
Dean and Rowena two bonded well when he began losing his memory and she was vital in reversing it. Following this event, Dean had a soft spot for her and grieved Rowena’s demise to the point where he cut contact with Castiel when his actions led to her death, proving how much she had meant to him.
Donna Hascum
Dean and Donna were similar when it came to awkward comedy, as the two bonded over their mutual love for stuff like fast food and donuts. Dean was also willing to dole out hugs to her, which was something he only reserved for very close people.
Donna never failed to make Dean laugh and in turn, he didn’t treat her like a ditz the way most people did. While their interactions only arose when they needed help from one another, they did have the utmost trust in their friendship.
Crowley
There are some things about Crowley that are overrated, but his friendship with Dean certainly was underrated. This was at its height when Dean was a demon, during which the two became pals who partied around in bars and reveled in their villainy.
Even after that, however, Crowley retained a soft spot for Dean as he would recall their good times and continued to help the Winchesters based on that. After Crowley’s demise, Dean went so far as to pray to Chuck to resurrect him, as he’d grown on him so much.
Jody Mills
Jody deserves a lot of credit for all the heroic things she did, being a hunter, a sheriff, and a motherly figure. Dean respected all of these attributes, although he found the most solace in her maternal instincts.
This was to the point where Jody acted like a parent to Sam and Dean. Whenever things escalated, Dean could rely on Jody, who orchestrated his and Sam’s rescue from the Bad Place.
Charlie Bradbury
Charlie was easily Dean's closest female friend. He appreciated her unique personality and loved the optimism she exuded. Almost as soon as they became friends, Dean likened Charlie to be the sister he never had, a feeling that only grew with time.
It was Charlie’s demise that pushed him over the edge with the Mark of Cain, as Dean couldn’t contain his grief at losing such a close friend. She was the perfect balance to his fierce nature, which is why their friendship worked so well.
Benny Lafitte
Having been around each other nonstop for a year in Purgatory, where they quite literally kept one another alive, Dean and Benny forged a brotherhood that he never forgot. Having spent his entire life considering every monster an enemy, Dean broke this belief after being around Benny.
Their bond was such that both of them did whatever they could to save each other’s lives, whether it was on Earth or Purgatory. Even years after Benny’s demise, Dean held hope to be reunited with him someday as their friendship remained alive for him.
Castiel
Their chemistry was such that it gave way for the Destiel ship among fans, as Dean found the best friend he never had growing up in Castiel. Ever since having been resurrected from Hell due to Castiel, Dean never forgot the connection he had with the angel.
Every time they were separated, Dean was beside himself with grief until they were reunited. They went through everything from Hell, Heaven, Purgatory, Apocalypse World, and the Empty, with their bond remaining firm. In the end, this was cemented forever as Castiel gave his life a final time to save Dean’s.