This study explores self-efficacy as an explanation for individual differences in participation in a manufacturing organization with a structured participation program. Participation covers three distinct dimensions of behavior: (1) decision-making pertaining to tasks, (2) good citizenship in the form of extra effort and helping others, and (3) contributing to improvement in work processes. Self-efficacy refers to an individual's belief that he/she can successfully perform an activity in a specific situation. The project was based on an action research design in which the first phase examined the dimensionality of participation self-efficacy, the relationship between participation self-efficacy and actual ratings of participation, and the relationship between perceptions of situational factors and self-efficacy. Exploratory factor analysis found preliminary support for the three proposed dimensions of participation self-efficacy and also for a fourth communication dimension. Weak (e.g., r=.27) and non-significant correlations were found between self-efficacy and actual participation ratings. Situational factors were examined as perceptions of barriers which were proposed to be inversely related to self-efficacy. As expected, negative correlations (ranging from -.28 to -.45) were found between perceptions of situational factors and participation self-efficacy. Phase two of the project evaluated a critical thinking training program designed to increase employee participation. A Pre-test Post-test! Nonequivalent control group design was used to study the influence of training on learning self-efficacy and participation self-efficacy. ANOYA and ANCOVA found no significant differences in post-training self-efficacy between the trained group and the control group. / Ph. D.