This chapter deals with consumer co-ops (co-operatives), while the preceding Chapter 20 deals with Worker Co-ops. Consumer and service co-ops basically differ from Producer/Worker co-ops by virtue of the economic relation their members have with the cooperative, as consumers versus producers or workers, and the related interests and benefits they promote. We review research on Consumer Co-op historical developments in Asia, Latin America, Europe, and North America. Other topics reviewed include activities of co-ops, origins, locations, getting involved, volunteering, sustainability, current challenges, internal organization, variations among co-ops, relations with other co-ops and national coordinating bodies, barriers to participation and effectiveness, and relations to public policy. The chapter provides definition of special terms, suggestions for usable knowledge, and ideas for future research.