Shared leadership, in which the role of the leader is shared across team members, has great potential, yet little is known about the conditions under which it may be more or less effective across cultures. We examine traditionalism and the extent of virtuality as features which may change the relationship between shared leadership and team effectiveness, among 211 individuals working in 56 teams in a multinational aerospace design collaboration. We find a 3-way interaction between traditionalism, virtuality, and shared leadership in predicting team effectiveness. When traditionalism was high, virtuality was essential for shared leadership and team effectiveness. The theoretical contributions and relevance for managers in utilizing shared leadership are discussed.