In this study, gender differences in the referral of children to mental health services were investigated.A total of 135 first-, second', and third-grade teachers read vignettes describing girls and boys with either externalizing or internalizing problems, and then evaluated the child described in each vignette concerning possible referral for mental health services. Results of this study identified three factors that help explain gender differences in referral. First, teachers are more likely to believe that boys need referral because boys tend to have the types of problems (externalizing) that teachers regard as being more in need of referral. Second, teachers are generally less likely to regard a child with problems as needing referral if that child is doing well academically (a pattern more common for girls). Third, teachers are less likely to believe that girls need referral because they are more optimistic that girls with problems will improve as they mature and that internalizing problems (the type girls tend to have) will improve through maturation. The implications of these findings for teacher training are discussed.