This study examined the Proteus effect in autistic and neurotypical participants via the video game, The Sims. Thirty-two participants (16 autistic, 16 neurotypical) participated in a free-play session of The Sims, playing as either an attractive or unattractive avatar. In line with predictions, participants who had played as the attractive avatar negotiated for a significantly larger share of a fictional pot of money during a post-play economic game. Further, participants who had used the attractive avatar engaged in significantly more exercise activities in-game and flirted more often with nonplayable characters. While there was some evidence to suggest that autistic people may be less resistant to peer influence in the economic game, this study shows for the first time how the Proteus effect can be demonstrated in autistic people. These findings have important implications for understanding how autistic people experience video games and may be leveraged to improve outcomes for autistic video gamers.