Background: Internationally, mental health and social care systems face significant challenges when implementing policy to prevent and respond to domestic violence (DV). This paper reviews the policy process pertaining to the national law on domestic violence prevention and control (DVPC) within the health system in Vietnam from 2003 to 2018, and critically examines the policy-making process and content, the involvement of key actors and the barriers to implementation within the health system. Methods: 63 policy documents, 36 key informant interviews and 4 focus group discussions were conducted in Hanoi city, Bac Giang and Hai Duong provinces. The policy triangle framework was used to analyse the development and implementation process of the Law on DVPC. Results: The Vietnamese government developed the law on DVPC in response to the Millennium Development Goals reporting requirements. The development was a top-down process directed by state bodies, but it was the first time that international agencies and civil society groups had been involved in the health policy development process. The major themes that emerged in the analysis include: policy content, policymaking and implementation processes, the nature of actors' involvement, contexts, and mechanisms for policy implementation. Policy implementation was slow and delayed due to implementation being optional, decentralization, socio-cultural factors related especially to sensitivity, insufficient budgets, and insufficient cooperation between various actors within the health system and other related DV support systems. Conclusion: The initial development process for DVPC Law in Vietnam was pressured by external and internal demands, but the subsequent implementation within the health system experienced protracted delays. It is recommended that the policy be revised to emphasise a rights-based approach. Implementation would be more effective if monitoring and evaluation mechanisms are improved, the quality of training for health workers is enhanced, and cooperation between the health sector and related actors in the community is required and becomes routine in daily work.