Human service nonprofits play an important role in communities across the United States. While existing research has studied how nonprofits engage beneficiaries in the evaluation of services, little research has been done to understand how human service nonprofits involve beneficiaries in the design of services. This research argues participatory design can be used to engage beneficiaries in program design. Through semi-structured interviews conducted with nine human service nonprofit professionals, this research sought to better understand how human service nonprofits involve beneficiaries in the design and development of service programs; and what barriers exist for human service nonprofits to do participatory design. These research findings provide a foundational understanding of how human service nonprofits use participatory design and uncover barriers to help inform the solutions necessary to increase participatory design use at human service nonprofits.