There has been an increased interest in teaching and learning Chinese language across many schools in Aotearoa / New Zealand (NZ). Chinese language teachers, particularly those new to the Aotearoa/NZ schools and education system, are confronted with (1) an educational environment that calls for learner-centred pedagogies and (2) an increasingly diverse classroom that requires these teachers to adopt pedagogical strategies that address and cater for diversity. In response to these needs, this article discusses a case study of a research-informed professional development (PD) workshop designed to support Chinese language teachers to (1) identify ways that diversity manifests in the Aotearoa/NZ classroom and (2) figure out how to design for learning whilst accounting for diversity in Aotearoa/NZ. The workshop promoted a discussion on diversity from an inclusive, heterogeneous perspective, and introduced teachers to contemporary conceptual ideas connected to ‘teaching-as-design’, and to the Activity-Centred Analysis and Design (ACAD) framework. Teachers (N = 19) were randomly assigned to groups of three to five. Groups were encouraged to collaborate on the design of learning tasks that incorporated TBLT (Task-Based Language Teaching) and addressed diversity in the classroom. Analysis of their design activities and produced artefacts reveals that teachers’ understanding of diversity comprised many characteristics, they held a positive attitude towards being responsive to diversity, and were able to experiment with new design concepts and ideas using the ACAD toolkit. In particular, teachers were able to successfully expand the design of their learning tasks to include social and material design elements to address learner diversity. Findings also reveal teachers’ emerging awareness of their dual role as facilitators and as teacher-designers.