<p>Parasitoids are important biological control agents, which play an active role in controlling agricultural and forestry pests. The diapause of parasitoids is crucial for controlling pest populations and preserving the ecological equilibrium in natural environments. Diapause has been studied for over 80&#xa0;years. To date, diapause has been studied in approximately 178 species of parasitoids, including major families such as Braconidae, Trichogrammatidae, Ichneumonidae, and Encyrtidae. Among them, at least five species including <i>Trichogramma dendrolimi</i>, <i>T. cacoeciae</i>, <i>T. japonicum</i>, <i>T. brassicae</i>, and <i>Aphidius gifuensis</i>, have been utilized for production and application using diapause manipulation in parasitoid rearing. The development of omics technologies has accelerated the study of the underlying mechanism, but there remains a lack of in-depth investigation. This article reviews the research progress of diapause in parasitoids, encompassing environmental and biological factors inducing diapause, biological, and physiological response after diapause, and the mechanisms involved in diapause. Additionally, the potential applications of diapause parasitoids are explored. A deeper understanding of the diapause phenomenon in parasitoids and its molecular mechanisms is sought, with the goal of offering more effective strategies for ecosystem management and agricultural production.</p>