The studies described in this paper explore the role of 3rd-party beneficiaries (e.g., customers, clients) in social dilemmas. Considering the impact of 3rd-party beneficiaries on cooperation is important because individuals value the impact their work has on others. We report three experiments that examine the effects, boundary conditions, and mechanisms associated with 3rd-party beneficiaries in social dilemma contexts. Results demonstrate that the salience of a 3rd-party beneficiary enhances cooperation, but only if that 3rd-party is seen as in need of help. Results also suggest that 3rd-party beneficiary effects on cooperation are mediated by task significance and positive self-image. Our findings extend the social dilemma paradigm to embrace the role of 3rd-party beneficiaries, and connect the literature on social dilemmas with the literatures on task significance and relational job design. Practically, our research offers managers suggestions for enhancing cooperation by managing the salience of external beneficiaries.