A high level of teacher self-efficacy is considered to be important for a successful and healthy teaching career. This preregistered 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, 95% 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 sociocognitive theory revealed that overall interventions including mastery experiences did not significantly differ from those without. However, interventions targeting only mastery experiences were the most successful for pre-service teachers (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.