The impact of climate change on reproductive decision-making is becoming a significant issue, with anecdotal evidence indicating a growing number of people factoring their concerns about climate change into their childbearing plans. Although empirical research has explored climate change and its relationship to mental health, as well as the motivations behind reproductive decision-making independently, a gap in the literature remains that bridges these topics at their nexus. This review endeavours to fill this gap by synthesising the available evidence connecting climate change-related concerns with reproductive decision-making and exploring the reasons and motivations behind this relationship. A systematic review using six databases was conducted to identify relevant literature. Included studies reported quantitative, qualitative, and mixed-methods data related to: (1) climate change, (2) mental health and wellbeing concerns, and (3) reproductive decision-making. Findings were synthesised narratively using a parallel-results convergent synthesis design and the quality of studies was appraised using three validated assessment tools. Four hundred and forty-six documents were screened using pre-defined inclusion criteria, resulting in the inclusion of thirteen studies. The studies were conducted between 2012 and 2022 primarily in Global North countries (e.g., USA, Canada, New Zealand, and European countries). Climate change concerns were typically associated with less positive attitudes towards reproduction and a desire and/or intent for fewer children or none at all. Four themes explaining this relationship were identified: uncertainty about the future of an unborn child, environmentalist views centred on overpopulation and overconsumption, meeting family subsistence needs, and environmental and political sentiments. The current evidence reveals a complex relationship between climate change concerns and reproductive decision-making, grounded in ethical, environmental, livelihood, and political considerations. Further research is required to better understand and address this issue with an intercultural approach, particularly among many highly affected Global South populations, to ensure comparability and generalisable results.