Purpose: It is vital in today's society that teachers are proactively involved in educational change. Given that proactive motivation is a critical driver of proactivity, this study aims to investigate how teachers' formal and informal workplace-learning experiences were connected with their proactive motivations to implement educational change. Design/methodology/approach: The authors used a qualitative case study approach to describe the relationships between teachers' formal and informal learning activities and their different proactive motivations. The authors collected data from 17 teachers via individual interviews and open-ended questionnaire and performed analyses using a continuous inductive and deductive coding process. Findings: The authors found that informal teacher learning can trigger three types of proactive motivation, whereas formal teacher learning is mainly connected with the can do and energised to motivations. The authors also found that formal and informal learning complement and compete with each other in shaping the can do motivation. Moreover, the authors found that informal learning played the dominant role in the reason to motivation, whereas informal and formal learning were separately connected to the energised to motivation. Practical implications: These findings indicate that greater attention must be paid to teachers' informal workplace-learning experiences. Specifically, teachers' informal learning experiences should be actively integrated into their formal workplace training to enhance their proactive motivation to educational change. Moreover, teachers' learning preferences and teaching experience should be considered in the design of teacher-training programmes. Originality/value: Based on the proactive motivation model of Parker et al. (2010), the authors have uncovered the mechanisms of workplace learning that drive teacher proactivity. The authors have examined the relationship between teachers' formal and informal workplace-learning and proactive teaching. The findings will assist policymakers and administrators to identify effective means of motivating teachers to engage in workplace learning.