Our purpose was to advance and test a theoretical model of the nature and function of trust in schools. Unlike other studies, ours specified school trust as a latent construct manifested through parent and teacher trust perceptions. We hypothesized that trust would have a larger direct effect on collective teacher efficacy and achievement motivation than on school performance. Furthermore, we predicted that the total effects of trust on school performance would be stronger than the total effect of poverty. We used structural equation modeling to test our hypotheses. Results support the prediction that trust provides a lubricant for effective school performance by having more direct influence on social conditions than on actual performance. We also found that trust attenuates the negative relationship between poverty and school achievement. (Contains 2 figures and 5 tables.)