Background. The success of academic institutions depends in particular on positive social relationships that fluctuate in terms of number and quality. They contain a complex network of interactions in which teachers exchange with others (administration, colleagues, and students) to increase their efficiency at work. Positive social relationships rely on trust as a social lubricant (Fullan, 2010). Trust is a key factor fostering collaboration and facilitating the exchange of information between parties (Hoy & Tschannen-Moran, 2003). Although many empirical studies have confirmed that transformational leadership plays a key role in teachers’ self- and collective efficacy (Leithwood & Sun, 2012), very few studies have demonstrated the mediating role of teacher trust in this relationship. Moreover, very few studies have simultaneously examined teachers' trust in three referents with whom they collaborate regularly (administration, colleagues, and students; Clément et al., 2020). Hypotheses. Therefore, we hypothesize that teachers’ trust in administration, colleagues, and students is a necessary condition between their perception of transformational leadership and their self- and collective efficacy. Sample (size and characteristics). Teachers from nine public colleges located in the Canadian province of Quebec agreed to participate in this study and responded to an online questionnaire (n=433; 61% women; Mage = 42.11, SD = 9.35; 64% tenured; Mexperience = 11.02, SD = 8.25). Results. The results using structural equations provide support for the proposed model (χ2 = 1611.513; df = 883; CFI = .907; TLI = .901; SRMR = .055; RMSEA = .044 [.040, .047]). The model presents two mediating paths: 1) leadership → trust in colleagues → collective efficacy, estimate = .124, p < .036; 2) leadership → trust in students → self-efficacy, estimate = .079, p < .066. Theoretical and practical implications, as well as directions for future research will be addressed throughout the presentation.