BACKGROUND: Climate change and mental health outcomes are two of the most pressing global crises. Despite the increasing global mental health burden, climate-related mental health outcomes research is nascent and isolated, with substantial gaps across regions and disciplines. Connecting Climate Minds is a global initiative connecting researchers, experts, and people with lived experience of adverse mental health outcomes to identify regional research needs and create a community to support improved climate-related mental health outcomes. METHODS: We focused on North America and Europe as part of the global Connecting Climate Minds effort, using semi-structured interviews, focus groups, regional dialogues (ie, discussions between experts in climate health, planetary health, human health, and mental health and with lived experience to discuss the climate threats most affecting their communities, their effects on mental health, and opportunities for action), and a literature review to identify crucial research gaps in climate change and mental health. We collected insights into priorities when addressing mental health outcomes related to climate change in Europe and North America; requirements for effective research, policy, and practice; and encouraging collaboration from a diverse community that included experts, researchers, practitioners from multiple disciplines, indigenous groups, and youth representatives. We used a qualitative framework analysis to identify consensus priorities. FINDINGS: Several themes emerged regarding research gaps. First, research into the effects of climate change on mental health is needed (eg, how pre-existing mental health outcomes are affected by climate disaster events, risk factors and protective factors, the effects of climate action or inaction on mental health, and economic costs). Second, investigating connections between climate-related mental health outcomes and Indigenous and other cultural practices (eg, the effects of climate change on Indigenous peoples and practices, cultural variations in mental health responses, and the effectiveness of integrating Indigenous and cultural knowledge into mental health interventions). Third, mixed-methods research is needed to explore the relationships between climate change, global and national economies, and governance and their associations with mental health outcomes. Fourth, evaluating social and cultural connectedness in mental health outcomes and climate change, community-level interventions, and the effectiveness of climate-education programmes that incorporate mental health considerations are research priorities. Finally, understanding how emerging technology can be used to understand climate-related mental health outcomes and use of technology to collect, analyse, and respond to population health data (with ethical considerations). INTERPRETATION: Connecting Climate Minds aims to psychologically equip people in Europe and North America to navigate the challenges of a changing climate. Climate-related mental health experts in should collaborate and encourage research and action that are proactive, community-led, and accessible. FUNDING: Imperial College London, the Wellcome Trust, and the Planetary Health Alliance via Harvard University.