This article provides greater understanding of factors influencing interpersonal trust in networks composed of public and nonprofit service providers. The present theoretical model identifies propensity to trust, the perceived trustworthiness of the trustee, the relationship between the trustee and trustor, and third-party relationships as influencing interpersonal trust. The model is tested using action research data collected from a network of local social service providers. Key findings include the following: (a) Successful past cooperation between a trustor and a trustee and structural equivalence increase the likelihood the trustor will perceive the trustee as trustworthy; (b) the frequency of interactions between the trustor and trustee, trust transferability, and the perceived trustworthiness of the trustee have a direct, positive impact on whether the trustor trusts the trustee; and (c) trust between the trustor and trustee has a positive impact on expected future cooperation.