The present study explored possible stereotypical beliefs, or myths, related to prejudice and discrimination toward transgender individuals in the US. In a 5 x 2 x 3 mixed factorial design, Amazon Mechanical Turk workers ( N = 1,450) read a description of a target depicted as a sexual predator, HIV-positive, having a mental illness, an ally of transgender people, or unfair to others. They then completed an intuitive judgment task regarding the target’s gender (male or female) and identity stigma detail (transgender, sexual minority, or no stigmatized detail), and provided feeling thermometer ratings for various groups. Results indicated that participants perceived mental illness as relatively representative of transgender people, but not HIV-status or sexual predation. Feeling thermometer ratings for transgender people were significantly lower than those for other gender/stigma categories and were negatively correlated with participant religiosity and conservatism. We discuss these findings in terms of gendered assumptions and present implications for gender-related stigma and the role of perceived mental illness in antitransgender prejudice.