Cognitive behavior theory indicates that situational determinants may have a substantial impact on substance use and relapse into use. The present study described situational use of marijuana in dependent individuals, analyzed relationships among various constructs in existing theory, determined their effects on treatment outcomes, and explored interactions with self-efficacy. Results were generally consistent with hypotheses. Use in negative affective situations was independently associated with psychological distress, maladaptive coping strategies, and poorer outcomes post-treatment. Additionally, negative affective use interacted with self-efficacy for psychologically distressing situations to produce differential outcomes. This study adds to the existing literature on situational marijuana use by establishing relationships with motives for use and lending support to the cognitive behavioral theory model.