This study investigated the effect of online summative and formative assessments on 30 Iranian English as foreign language teachers’ teaching competences. Everything being equal in terms of participant homogeneity and classroom video-based teacher induction for 21 sessions, significant differences in teaching competence improvements on three assessment interventions were sought using pretest/posttest time series design. The assessment interventions included online summative assessment (teachers receiving online feedback after their classroom observation), teachers online portfolio writing formative assessment (teachers receiving feedback after content analysis of their portfolios) and online collaborative discussion formative assessment (ECDF) (teachers’ receiving feedback in the discussion forum). Classroom observation, content analysis of e-portfolios, and log analysis of ECDF were used to code indicators of teacher competence improvements according to a scoring schema to fill teacher balanced score card (TBSC). The teacher competences were measured on TBSC in pre- and post-assessment interventions. The results of Paired sample t test and ANCOVA (analysis of covariance) indicated improved teacher competences across all-time series measures. Comparatively, teaching competences were more affected in ECDF assessment intervention where collaborative reflection and feedback were exchanged. Implications for education practitioners were provided and suggestions were offered for further research in the light of the limitations of the study.