Provides a selective overview of accomplishments in behavioral science, with a focus on how culture influences the course of mental illness. Anthropological and cross-cultural studies have demonstrated that cultural beliefs about the nature of mental illness inform the community’s view of its course and treatment and, in turn, the actual duration of the illness; thus, it is imperative that today’s health care workers understand cultural differences and respond to the special perspectives of ethnic minorities. Basic psychological processes are expressed differently from culture to culture, including the sense of self and self-esteem, the experience of emotion, and the motivation to achieve excellence or success. Moreover, as cultural diversity increases in the United States, it is essential to understand how belonging to an economically disadvantaged racial, ethnic, or cultural group promotes or inhibits mental health and psychological functioning. Important directions for future research include exploring how ethnicity influences social cognition and achievement motivation; why poor and minority persons are at elevated risk for misdiagnosis and involuntary hospitalization; and how the mental health of immigrants is influenced by such factors as acculturation, socioeconomic status, the presence or absence of an accessible ethnic community, and support systems available in the work environment.