Global warming threatens food security. Rice (Oryza sativa L.), a vital food crop, is vulnerable to heat stress, especially at the reproductive stage. Here we summarize putative mechanisms of high-temperature perception (via RNA secondary structure, the phyB gene, and phase separation) and response (membrane fluidity, heat shock factors, heat shock proteins, and ROS (reactive oxygen species) scavenging) in plants. We describe how rice responds to heat stress at different cell-component levels (membrane, endoplasmic reticulum, chloroplasts, and mitochondria) and functional levels (denatured protein elimination, ROS scavenging, stabilization of DNA and RNA, translation, and metabolic flux changes). We list temperature-sensitive genetic male sterility loci available for use in rice hybrid breeding and explain the regulatory mechanisms associated with some of them. Breeding thermotolerant rice species without yield penalties via natural alleles mining and transgenic editing should be the focus of future work.