Heat waves have emerged as an escalating climate threat, triggering cascading disruptions across food, energy, and water systems, thereby undermining resilience and sustainability. However, reviews addressing heat wave impacts on the food–energy–water (FEW) nexus remain scarce, resulting in a fragmented understanding of cross-system interactions and limiting the ability to assess cascading risks under extreme heat. This critical issue is examined through bibliometric analysis, scoping review, and policy analysis. A total of 103 publications from 2015 to 2024 were retrieved from Web of Science and Scopus, and 63 policy documents from the United States, the European Union, Japan, China, and India were collected for policy analysis. Bibliometric analysis was conducted to identify the most influential articles, journals, countries, and research themes in this field. The scoping review indicates that agricultural losses are most frequently reported (32), followed by multiple impacts (19) and cross-sectoral disruptions (18). The use of spatial datasets and high-frequency temporal data remains limited, and community-scale studies and cross-regional comparisons are uncommon. Mechanism synthesis reveals key pathways, including direct system-specific stress on food production, water availability, and energy supply; indirect pressures arising from rising demand and constrained supply across interconnected systems; cascading disruptions mediated by infrastructure and system dependencies; and maladaptation risks associated with uncoordinated sectoral responses. Policy analysis reveals that most countries adopt sector-based adaptation approaches with limited across-system integration, and insufficient data and monitoring infrastructures. Overall, this study proposes an integrated analytical framework for understanding heat wave impacts on the FEW nexus, identifies critical research and governance gaps, and provides conceptual and practical guidance for advancing future research and strengthening coordinated adaptation across food, energy, and water sectors.