Climate change is disrupting food security around the world, with uneven impacts between regions and populations. Through direct and indirect pathways, climate change affects the availability, accessibility, utilization, and stability of food systems. In turn, climate-related food insecurity may cause or exacerbate mental health problems by affecting the biological, psychological, social, and cultural determinants of mental health. These mental health impacts of climate change and food insecurity vary based on age, gender, and sociocultural context, and they intersect with other forms of socioeconomic precarity. Climate change is thus connected to human mental health through complex chains of causation, involving dynamic pathways that extend from the planetary to the individual level of analysis. In this chapter, we examine the impacts of climate change on mental health through its effects on ecosystems and food insecurity. After defining food security, we consider the consequences (current and future) of climate change on natural systems and the pillars of food security. We review epidemiological and qualitative evidence of the influence of food insecurity on mental health. Drawing from our experience in the Arctic, we present a case study of how climate change specifically impacts food security and mental health in Inuit Nunangat. We conclude by discussing some ways to mitigate, and respond to, climate change at different scales, from local to global, and by outlining ways forward for research and policy at the interface of climatic, food, and health systems.