Americans increasingly distrust their educational institutions and the people who work in them. This paper is about the salience of social trust in urban schools and its implication for school reform. The paper describes outcomes of a 5-year project that explored Chicago's (Illinois) attempt to use expanded local participation as a lever for school renewal. The research was based on the notion that the social qualities of trust, respect, and caring are integral to the operations of good urban schools. The paper examines three role relations critical for sustained school change: teacher-teacher, teacher-principal, and teacher-parent relations. Field-work data were gathered through interviews with the principal, selected Local School Council members, and observation. Empirical data were obtained from a survey of students and 1,462 teachers at 64 schools in a probability sample and a survey of students and 4,682 teachers in 206 schools in a volunteer sample. The paper argues that productive collective actions are more likely to occur when relational trust is present among organizational members. In the high-trust Chicago schools, a majority of teachers reported strong tendencies toward innovation. Relational trust creates an environment where individuals share a moral commitment to act in the interests of the collectivity, and this ethical basis for individual action constitutes a moral resource that the institution can draw upon to initiate and sustain change. Finally, relational trust must be founded on voluntary commitments. Contains 5 tables and 27 endnotes. (LMI)