13 Reasons Why features multiple LGBTQ+ characters, including openly gay Tony Padilla, whose stable relationship is depicted positively. Other characters like Alex Standall and Tyler Down explore their bisexuality and gender identity, respectively, with arcs focused on self-discovery and acceptance. While some characters face struggles related to their identity, these are generally framed as external societal pressures, contributing to a net positive portrayal.

13 Reasons Why features Casey, a trans male character, as part of the main friend group. His trans identity is acknowledged but not central to the show's primary narratives. The portrayal is largely incidental, neither extensively affirming nor problematic, as his identity is presented as a characteristic without significant exploration of related challenges or triumphs.

Several characters from the original novel, including Jessica Davis, Zach Dempsey, Courtney Crimson, and Tony Padilla, who were canonically white in the source material, are portrayed by actors of different races in the 2017 show adaptation.