Public attitudes toward transgender individuals in the United States have shifted in recent years, with growing opposition to gender-affirming policies and increasing levels of anti-trans sentiment. Given the implications of public opinion for the well-being and rights of transgender people, it is essential to examine the psychological and social factors that shape transprejudice. The present study investigated the role of religious fundamentalism (RF), social dominance orientation (SDO), and gender in predicting attitudes toward transgender individuals. A total of 364 participants from psychology courses at two universities completed measures of trans attitudes, SDO, religiosity, religious fundamentalism, and demographic information. Regression analyses showed that identifying as male and having higher SDO, religiosity, and religious fundamentalism were associated with more negative attitudes toward transgender people. Mediation analyses showed that the effect of gender and the effect of religiosity on trans attitudes disappeared when controlling for SDO and RF respectively. Additionally, we found that participants who embraced Abrahamic religions that preach binary conceptions of gender had more negative views of trans people and that religiosity was more strongly associated with beliefs about sex and gender, compared to other dimensions of transphobia. These findings suggest that rigid ideological belief systems related to RF and SDO play a significant role in fueling negative attitudes towards trans people, highlighting the need for interventions addressing authoritarian and dominance-based worldviews and combating harmful religious dogma to promote greater equality and inclusion for trans people.