The Hong Kong Education Bureau recommends that primary school pupils' mathematical achievement be enhanced via collaborative discussions engendered by group work. This pedagogic change may be hindered by Confucian heritage classroom practices and Western-dominated group work approaches that predominate in Hong Kong. To overcome these obstacles, we introduced a relational approach to group work in a quasi-experimental study. Our sample included 20 teachers randomly allocated to experimental (12) and control (8) conditions and their 504 mathematics pupils (aged 9-10). The relational approach focused on the development of peer relationships in a culturally appropriate manner and was implemented over 7 months. Pupils were pre-/post-tested for mathematical achievement and systematically observed, and the teachers were assessed for subject knowledge and pre-/post-tested for pedagogic efficacy. Analysis of covariance (ANCOVA) and hierarchical linear modeling (HLM) results show enhanced mathematical achievement, supported by improved peer-based communication skills and time-on-task for the experimental pupils. Experimental teachers raised their pedagogic efficacy. Results indicate the potential of the relational approach for boosting academic achievement via enhanced child-peer-teacher interaction and the need to reassess the role of peer-based latent collectivist learning in Confucian heritage classrooms.