Attribution theory provides a framework for examining personal and interpersonal motivation for collaborative projects. Undergraduates were asked to read vignettes concerning student dyads engaged in collaborative projects. The vignettes systematically varied on outcome of the project, student self-ability, student self-effort, partner ability, and partner effort. Participants responded to Likert items measuring personal affect of shame, guilt, and pride; interpersonal affect of pity, anger, and gratitude; and expectations for performance on future projects. Ability and effort attributions were expected to lead to different emotional consequences and future expectations, because they differ on the dimensions of controllability and stability. Overall, student motivation was tied more closely to effort than ability. Specific results are discussed within the framework of attribution theory.