A chronological overview of the development of NGOs from ancient precursors through to the latest transformations in the twenty-first century is offered in this chapter. It emphasizes the significant impacts NGOs have had in major world historical transformations, the interactions between NGOs and their historical contexts, and the cyclical dimensions to NGOs’ historical development. The coverage is broad, encompassing both advocacy and service organizations, and stressing the need to take into consideration developments beyond Europe and North America. The analysis draws from both a synthesis of insights from the expanding body of transnational historical research in the field, as well as from literature in related disciplines and from primary sources. The chapter culminates in a discussion of the conclusions that may be drawn from historical experience in considering challenges confronted by NGOs in the present day.