Public relations literature on corporate social responsibility (CSR) has long detailed the impact of CSR outcomes for corporations. This study seeks to understand how CSR influences the nonprofit partners involved in these initiatives and what types of CSR partnerships lead to nonprofit supportive intentions. This study merges perspectives on organization-public relationships (OPR) with nonprofit management literature. An online 2 (NPO reputation: low vs high) x 2 (partnership duration: short vs. long) x 2 (CSR fit: low vs. high) experiment was conducted. A few key factors emerged in the analysis: Positive nonprofit reputation strongly predicted all OPR outcomes and mission accomplishment. Unexpectedly, the short-duration condition led to more positive outcomes and intentions. Fit did not seem to have a direct effect on outcomes, but the high-fit, short-duration partnership led to increased levels of all outcomes. For mediation, satisfaction and commitment had the strongest indirect effects on nonprofit supportive intentions (donation, volunteer, and word-of-mouth). This study expands the understanding of CSR effects on nonprofit partners, specifically by showing how different CSR partnership types play a role in the relationship-building efforts of nonprofits. Additionally, demonstrating how mission accomplishment can strengthen these relationships helps to disentangle the unique position of nonprofits in CSR, whose reputation and mission are at stake.