This study investigated the similarities and differences between a voluntary organization and a labour union with respect to leadership (transformational transactional), work beliefs (Marxist humanistic), psychological involvement, inter-role conflict, commitment, and participation. Seventy-seven union surveys (response rate = 12.8%) and 212 volunteer surveys (response rate 36.3%) from Eastern Canada provided leader and non-leader samples for each organization. Volunteers were more psychologically involved and committed than union members. This result was attributed to higher levels of transformational leadership and greater opportunities for socialization and member interaction in the voluntary organization. Union members, as expected, reported higher levels of Marxist work beliefs than volunteers. However, both samples reported similar levels of humanistic work beliefs and inter-role conflict. These results replicated previous research in union settings and extended some of these findings to the voluntary setting. Overall, comparisons between labour unions and voluntary organizations appear to be a good mechanism for obtaining insight into the workings of both types of organizations.