Relational values associated with meaningful and just human–environment relationships (e.g. care and responsibility) have been proposed as motivating ‘upstream’ participation in Payments for Watershed Services (PWS). However, the way relational values are affected by and interact with PWS remains poorly understood. We reviewed 50 studies of social outcomes of PWS and found that approximately half assessed or discussed relational values. This included changes in relational values presented positively, such as amplifying values and norms around care for land; negatively, such as undermining traditional practices and intergenerational learning; and influencing other outcomes, such as links between land ties and human health. To improve understanding of the full suite of outcomes linked to the effectiveness, durability, and equity of PWS, we propose a research agenda based on locally-based relational value systems that include, for example, place-based conceptualizations of responsibility, care, and relation to the natural world.