Background: Middle leaders are well placed to exert a positive influence on teacher learning, due in part to their proximity to the classroom. However, to maximise that potential, more needs to be understood about the complex connections between instruction-oriented middle leadership and professional learning, particularly in non-Western contexts. Purpose: This study, undertaken in a Chinese context, investigated how middle leaders, specifically those who headed teaching-research groups (TRGs), enacted their instructional leadership to influence teacher learning and build teacher capacity. Method: A qualitative, multi-case design was employed. Participants included 6 vice-principals, 18 TRG heads and 24 classroom teachers. Data collection, in the form of semi-structured interviews, observations, and field notes, was conducted over four months in six schools in China. Data analysis involved the synthesis of participant narratives to identify how middle leaders made sense of, and promoted, teacher learning through their instructional leadership. Findings: Analysis allowed themes and sub-themes to emerge, suggesting four domains of leadership practice: (i) nurturing teacher job-embedded learning, (ii) creating a climate conducive to teacher learning, (iii) engaging teachers in school-based action research and (iv) mobilising external resources to develop teachers. From this, an early-stage conceptual model was created, describing how middle leaders used their instructional leadership as a primary pathway of influence, and how they emphasised relational bonds and organisational structure to stimulate teacher learning. Conclusion: The findings provide insights into middle leadership in the Chinese context, yielding a view into core practices of middle leadership for teacher learning, and drawing attention to teacher development practices that are relevant in other contexts internationally. Tapping into the potential of the middle leader to support teachers' professional learning can contribute to wider school improvement, ultimately benefitting all learners.