Renewable energy is critical for combatting climate change and the global sustainability crisis. Rooftop solar panels offer one of the cleanest forms of renewable energy, with residential installations particularly effective in reducing household carbon dioxide emissions. The Vietnamese government recently implemented a renewable energy strategy involving the launch of a rooftop solar initiative. This has led to the highest level of rooftop solar uptake in Southeast Asia, with generous feed-in tariff (FiT) rebates that greatly exceed those provided by neighbouring countries including Australia. This study is one of the first to investigate the factors influencing the adoption of household rooftop solar in Vietnam, including the impact of the government’s feed-in tariff initiative. In summary, this research has applied the theory of planned behaviour (TPB) and used structural equation modelling (SEM) to investigate the attitudes and intentions of 296 Vietnamese households towards rooftop solar installation. The analysis reveals the significant impact of the Vietnamese government’s solar incentive scheme and the motivating role of innovativeness, expectations and environmental knowledge, as well as the impact of subjective norms on solar panel uptake. As anticipated, monetary barriers restricted installation intentions. Although, unlike some other consumer TPB studies this research found that brand trust does not play a predictive role in intentions to install rooftop solar, perhaps due to lack of familiarity with solar energy product brands. These findings will likely inform future government policies and support businesses trading in solar energy products. This study will also be of interest to academics and policymakers in other countries seeking to understand and promote the adoption of rooftop solar.