<p>Rising global temperatures and the increasing frequency of heat waves&#xa0;results in climate change and pose a major constraint on rice (<i>Oryza sativa</i> L.) productivity. Rice is highly sensitive to elevated temperatures during key developmental stages, including panicle initiation, meiosis, anthesis, and early grain filling. During these stages, heat stress reduces pollen viability, disrupts anther dehiscence, lowers spikelet fertility, and impairs grain filling. At the physiological level, heat stress accelerates respiration, destabilizes cellular membranes, suppresses photosynthesis, and alters assimilate partitioning, leading to significant yield penalties. Recent advances have deepened understanding of the genetic and regulatory bases of heat tolerance, highlighting the roles of quantitative trait loci, heat-responsive genes, transcription factors, phytohormone signaling pathways, and epigenetic regulation. In parallel, advances in phenotyping, including controlled-environment screening and high-throughput field-based platforms, have improved the precision of heat-adaptive trait evaluation. These developments are increasingly integrated into breeding strategies such as marker-assisted selection, genomic selection, and genome editing to improve heat tolerance alongside yield and grain quality. However, the expression of heat tolerance remains strongly stage-specific and is influenced by genetic background and genotype × environment interactions. This review synthesizes current knowledge on heat stress responses in rice and discusses their application in breeding programs. Future progress will depend on robust functional validation of key regulators, integration of multi-omics data with predictive breeding models, and broadening the genetic base of heat tolerance to sustain rice production under warming climates.</p> Graphical Abstract <p></p>