BACKGROUND: People with mental disorders bear an excessive burden of oral diseases. This burden can exacerbate the personal, social and economic impacts of mental disorders. There is a need for transformational research to tackle this problem, which should start with co-setting research priorities with people with lived experience and key stakeholders. OBJECTIVE: This national Priority Setting Partnership (PSP) aimed to identify the top 10 research priorities for oral health among people with mental disorders. METHODS: Following the James Lind Alliance approach, this three-stage PSP engaged people with mental disorders, carers and staff of all levels and decision-makers from healthcare, social care and non-governmental organisations. In stage 1, questions for research were gathered via an online survey. Summary questions were then formed and checked against existing evidence. In stage 2, unanswered questions were compiled into an online shortlisting survey. In stage 3, a consensus workshop was held to determine the top 10 research priorities. FINDINGS: From 1214 questions received in stage 1, 60 unanswered questions were formed. Based on 2377 shortlisting survey responses, the 25 top-ranked questions were taken to the consensus workshop, where the top 10 research priorities were determined by 27 participants. The most important research question was 'What are the best ways to integrate oral health within physical health checks and follow-up care for people with severe mental ill-health?' Other questions focused on the capability of primary care, mental health and dental teams in supporting oral health, integrated system-level models of dental care and financial incentives for professionals. DISCUSSION: This PSP identified the top 10 research priorities for oral health among people with mental disorders, which would guide future research and funding aimed at reducing the stark inequalities in oral health between this group and the general population. CLINICAL IMPLICATIONS: Addressing the priorities identified in this consultation through transformational research would lead to impactful changes in healthcare and public health practice and policy. This in turn would address the burden of oral diseases among people with mental disorders and contribute towards improving their mental and physical health and recovery.