The Amalgamated Transport & General Workers’ Union (ATGWU) pioneered a strategy of organizing through the affiliation of mass membership associations of informal minibus taxi workers and motor cycle (boda-boda) drivers. Through the strategic use of their associational, structural, and societal power membership of the union increased dramatically, police harassment declined, internal conflict within the associations was reduced, and the conditions of informal women transport workers improved. Trade Unions in Transformation is an FES project that identifies unions’ power resources and capabilities that contribute to successful trade union action. This study features among two dozen case studies from around the world demonstrating how unions have transformed to get stronger.