The relationship between religious fundamentalism, humor, and psychological well-being was examined with a sample of individuals (n = 109) being treated for drug abuse in a court-mandated AA outpatient program. Three separate factors of religious fundamentalism were found through exploratory factor analysis of the Revised Religious Fundamentalism Scale, and these were named Righteous-Evil Worldview, True Religion, and Scriptural Literalism. Psychological well-being of individuals in court-mandated outpatient substance abuse treatment was found to be correlated with high levels of humor but not religious fundamentalism. Psychological well-being and humor were found to be related to satisfaction with services; no relationship was found between religious fundamentalism and satisfaction with services. One factor of religious fundamentalism, Scriptural Literalism, was found to be associated with high levels of depression and paranoia/hostility. Implications of these relationships for treatment and understanding of religious fundamentalism and psychological well-being are discussed.