This study used an experimental vignette design to examine whether school psychology students' attitudes toward a teenager in a case vignette varied based on whether or not they believed the teen to be transgender. Transgender status was conveyed indirectly through names (e.g., by indicating that the student with the legal name "Anthony" had requested to be called "Alyssa"). It also examined whether attitudes toward transgender boys and transgender girls differed, and the degree to which transgender-related training and experience affected attitudes. A 2 (Gender Status: cisgender vs. transgender) × 2 (Gender Identity: male vs. female) ANOVA indicated that participants had more supportive attitudes toward a transgender teen experiencing issues in school related to a name change and a behavior concern than toward a cisgender teen with the same issues, F(1, 421) = 121.59, p < 0.001. Gender Status and Gender Identity significantly interacted to affect attitudes, F(1, 417) = 10.83, p = 0.001. A test of simple effects indicated that participants were more supportive of transgender girls than transgender boys, p = < 0.001. However, participants' attitudes regarding cisgender boys versus girls did not differ significantly. Having had training about transgender issues, professional experiences with transgender individuals, or personal experience with transgender individuals correlated significantly with attitudes. School psychology programs are advised to add required training in this area and to focus on increasing supportive attitudes toward transgender boys in particular.