Producer organizations (POs) receive substantial attention and policy support, given their potential to contribute to pro-poor rural development. Here, we first synthesize decades of empirical research in the form of five stylized facts—common and largely unchallenged conclusions—about POs. Then, we explore these stylized facts using several secondary and primary data sets. We confirm some stylized facts, challenge others, and highlight which ones lack empirical evidence to derive policy implications and directions for future research. We highlight largely overlooked low and regionally biased participation rates and suggest that future research should pay more attention to the diverse forms and characteristics of POs.