Social media communication is attractive for non-profit organizations (NPOs); however, the channels of social media are not homogeneous; a factor not sufficiently considered by empirical research. We address this gap by looking into the moderating effect of social media channel choice on the impact of brand trust on process and outcome quality. By surveying 174 customers of an Austrian NPO, we analyze different social media channels to investigate whether (1) the established wisdom of service marketing regarding the positive impact of brand trust on service quality holds in the social-media context and (2) whether the choice of social media channel moderates these relationships. The results confirm the established model of service quality. Knowledge from traditional marketing can still be applied in a digital environment. However, the moderation analysis highlights the relevance of social media channel choice and illustrates different effects on YouTube, Facebook, and Instagram. We discuss the implications.