The underlying religious purpose of missionary expatriation influences the definition and forms of missionary expatriation. In combination with environmental trends and paradigm shifts, this mission worldview creates a unique and dynamic context for expatriation researchers. This chapter describes various types of missionary expatriation including traditional (frontier, professionally qualified, spouse, community development and humanitarian, tent maker, and business as mission). Research areas in each type of missionary are briefly discussed. A brief summary of missionary expatriate research literature focuses on member care topics including family adjustments, third-culture kids (TCKs), re-entry and adjustment in host country/ies, care support, burnout, persecution, and motivation. Areas for further research and approaches to missionary expatriate research are identified and discussed as well.