There is increasing evidence of negative mental health implications associated with climate change. However, more knowledge is required to inform effective responses. This study systematically reviewed literature regarding the relationship between climate emotions and mental health in adults. The goal was to synthesise existing research and identify future research priorities. The review followed PRISMA guidelines and involved searching seven electronic databases. The inclusion criteria specified peer-reviewed studies published in English after 2000, focusing on climate emotions and mental health in participants over 18 years old. Two authors independently reviewed the studies and assessed their quality. Out of 8,495 identified papers, 36 studies meet the criteria. Most studies included in the review were cross-sectional (n = 27) and used quantitative descriptive surveys (n = 27). A large majority of studies primarily involved participants from high-income countries (n = 32) and were published between January 2020 and January 2023 (n = 26). Results from the included papers suggest a relationship between climate emotions and negative mental health in most cases (30 out of 36). However, this finding must be interpreted cautiously since just over half of included studies were considered lower quality (19 of 36). Future research should aim to improve the conceptual clarity of climate emotions and explore potential causal and resilience factors. Additionally, investigations should consider vulnerable populations outside of high-income countries. Furthermore, increased collaboration between researchers and practitioners is necessary to improve conceptual coherence, and practice.