This chapter provides an overview of the literature on mobility in developing countries. Explicit distinctions are drawn between directional and nondirectional measures, absolute and relative measures, and combinations thereof. Although, the scarcity of panel data has hindered the measurement of mobility for many countries, this chapter pays particular attention to the recent development of panel-free mobility measures. Applying these methods to data from 122 countries reveals contrasting trends: rapid but unequal growth in Asia and slower yet equalizing growth in Africa. The review concludes with future research directions.