Drawing on a sociocultural perspective, this article analyses a Cambodian student-centred policy named Effective Teaching and Learning (ETL) to explore how this policy is practiced, or constructed through the negotiation among policy actors. Tensions I found in the policy between radical orientation toward the transformation of knowledge and its conservative approaches based on the transmission of knowledge, was used as a scaffold to make sense of the politics in education policy-making. In-depth interviews with national and international policy actors indicated that ETL's intended transformation orientation was altered to fit more closely with the existing top-down, transmission-based structure over the course of negotiation. Such tensions, however, allowed various stakeholders to take part in pedagogical reform -- not necessarily ETL per se -- bringing their distinctive perspectives. These findings suggest the importance of shedding light on the sociocultural nature of education policy-making, an aspect that has been less explored in current policy implementation research.