["Agribusiness, EarlyView. ", "\nABSTRACT\nWe analyze the impact of collective action through farmer‐based organizations (FBOs) on smallholders' farm performance and income inequality in Ghana, Benin, The Gambia, and Mali. We find that FBO membership increases cereal yield in Ghana and The Gambia, legume yield in Mali, ruminant numbers in Benin and The Gambia, and total farm income in Ghana and Benin. While FBOs promote income equality among smallholders in Ghana, they widen inequality in the three countries. Ensuring inclusive participation, especially for vulnerable rural farmers and women, is key to equitable benefits from collective action.\n"]