Who is the third strongest hero in Dragon Ball Super, Gohan or Android 17? The anime doesn't provide a clear answer to this question, but the manga reveals that Gohan has the edge over Android 17. Clearly, the two strongest main heroes are Goku and Vegeta, with Gohan, Android 17, Buu, and Piccolo also being counted amongst the planet's most powerful defenders. But for the most part, the character who holds the distinction of being the third strongest has been up for debate.
Before Dragon Ball Super, Android 17 wouldn't have even been in the conversation, as he was left behind after the Cell Saga. Dragon Ball Super brought him back into the fold by having Goku recruit him for Universe 7's Tournament of Power team. Android 17 proved himself a highly capable warrior by fighting on par with Super Saiyan Blue Goku. Android 17 went on to become the breakout star of the Tournament of Power, outlasting fighters like Gohan, Caulifla, Hit, Top, and more. Though not as strong as Goku or Vegeta, Android 17 survived the final battle with Jiren and became the last man standing when it was all over.
The Tournament of Power arc in Dragon Ball Super makes the case for Android 17 to be the anime's third strongest hero, but is he really more powerful than Gohan? The manga continuation of Dragon Ball Super provides the answer to this question. During the Galactic Patrol Prisoner arc, the Z-Warriors had to deal with Goku and Vegeta being off-world. It was stated by Piccolo that with them gone, Gohan is the strongest person on Earth. Considering that Piccolo observed the performances of both fighters in the Tournament of Power, this serves as confirmation that Gohan is indeed stronger than Android 17.
Since Dragon Ball Super turned Android 17 into a force to be reckoned with again, the comparison to Gohan has been a subject of debate for fans. Gohan lost to Goku, whereas Android 17 fought Goku to a tie, with it being suggested that both characters were holding back. But, it's important to note that Goku did not hold back at all against Gohan. Gohan forced Goku to use his Kaio-ken technique, which at the time was the limit of Goku's power.
Both Gohan and Android 17 seemed to struggle equally against Universe 11's Top, so it was clear then that the two were somewhat close in power levels, but far away from Goku and Vegeta. Gohan couldn't beat Universe 11's third strongest fighter, Dyspo, without help from Golden Frieza, and Android 17 wasn't able to do much against Jiren. However, in the manga version of the story, Gohan accomplished an impressive feat by fighting Kefla to a stalemate, which makes him more formidable than most may have realized. In the anime, it took Goku's incomplete Ultra Instinct form to eliminate Kefla. In light of this, it's not too hard to believe that Gohan is at the very least slightly more powerful than Android 17. In any case, Gohan has succeeded in redeeming himself and is on his way back to being relevant again.