This study analyzes the factors that have facilitated Vietnam’s recent rapid solar and wind power expansion and draws policy insights for other member states of the Association of Southeast Asian Nations (ASEAN). A policy-mix analysis focusing on targets, incentive instruments, enabling regulations, and policy implementation is carried out, informed by semi-structured interviews with 20 Vietnamese experts during the period January–March 2021. A comparative analysis between Vietnam and the other ASEAN countries provides policy insights. Generous feed-in tariffs are found to have been a key driver, with income tax and land lease payment exemptions also being important. The main barriers include a high level of policy uncertainty and an underprepared transmission grid. Vietnam’s case indicates that a strong price signal and a supportive investment environment can pave the way for rapid solar and wind power uptake. Another key lesson is that early preparation of transmission systems for solar and wind electricity is needed to maximize the potential for expanding the use of these technologies.