A high level of teacher self-efficacy is considered to be important for a successful and healthy teaching career. This pre-registered meta-analysis focuses on whether and to what degree interventions can promote teacher self-efficacy. We included 115 studies representing 11,284 pre-service and in-service teachers in our meta-analysis. Interventions had a significant, positive effect on the promotion of teachers’ self-efficacy (g = 0.47, RVE SE = 0.04, CI = [0.40, 0.54]) with no significant differences between pre- and in-service teachers. A fine-grained coding and systematic review of the targeted sources of self-efficacy according to Bandura’s socio-cognitive theory revealed that overall interventions including mastery experiences did not significantly differ from those without. However, for pre-service teachers, interventions targeting only mastery experiences were the most successful (g = 0.62, RVE SE = 0.11, CI = [0.35, 0.88]). Based on further moderator analyses, we recommend interventions to integrate reflective elements. Finally, future research should apply stricter study designs and more detailed intervention descriptions.