The present study investigated the influence of sexual stereotyping on the diagnostic impressions and treatment expectations of gay and straight male patients. Italian male, straight, licensed psychotherapists (N = 152) were presented with clinical vignettes that described a gay (versus straight) male patient reporting either a straight-stereotypical disorder (i.e., rage dyscontrol) or a gay-stereotypical disorder (i.e., sexual compulsivity). Results revealed that treatment efficacy expectations were influenced by the patient's sexual orientation and the stereotypicality of the disorder. Specifically, psychotherapists anticipated fewer benefits from psychotherapy when gay patients reported a sexual disorder rather than a rage disorder. Furthermore, explicit and implicit levels of sexual prejudice did not play any role in driving such results. Taken together, these findings reveal that sexual stereotyping might exert its subtle effects among clinicians by influencing their clinical evaluations.