A vast unmet demand exists for housing finance for low-income populations in the developing world. Though solutions have yet to reach significant scale, either at governmental or private levels, the microfinance industry has recently made great strides in this area. Housing microfinance (HMF) has shown signs of its potential to reach scale. ACCION International and Habitat for Humanity International joined efforts to conduct a study covering ten of ACCION’s partners in Latin America, representing more than 90 percent of the ACCION Network’s housing portfolio. The objective of this research was to learn about the key success factors as well as challenges and barriers for reaching scale in housing.