This study sought to identify predictors of suicidal behavior among college students who are psychotherapy clients, as well as to determine underlying classes of clients with suicidal ideation. Data were gathered from 101,570 clients, 391 of whom engaged in suicide behavior during treatment. Regression analyses revealed that suicide behavior was positively associated with 3 pretreatment variables: depression, prior suicide behavior, and prior nonsuicidal self-injury. Four latent classes of clients with suicidal ideation were identified that were named “prior ideation,” “extensive risk,” “prior treatment,” and “circumscribed depression.” The number of clients in each class varied widely, as did the relative risk of suicide behavior. Implications for treatment, suicide assessment, and suicide prevention are discussed.