This article analyzes the impact of producer organizations (POs) on dairy farmers’ self-assessed experiences of unfair trading practices (UTPs) and negotiation power. We employ an endogenous switching regression (ESR) model using cross-sectional survey data collected in four EU countries: France, Germany, Spain, and Poland. The results show rather mixed impacts of PO membership. PO membership reduces the likelihood of farmers reporting UTPs. On the other hand, PO membership is found to reduce the self-assessed negotiation power of PO members. The estimated impact of PO membership is found to be largest for smaller farms.