Parasitoids are key regulators of insect populations, particularly those associated with decomposing organic matter and synanthropic environments. This study analyzed parasitoid–Diptera interactions across different environments and substrates, with emphasis on parasitism patterns, species diversity, host associations, and ecological relationships. Data were compiled from experimental studies conducted in Brazil, including forest, urban, pasture, livestock, and agricultural systems. Sampling methods included baited traps, exposure of organic substrates, recovery of pupae, and laboratory emergence of Diptera and parasitoids. Parasitism rates were standardized to allow comparisons among studies. In addition, the quantitative data available in several articles enabled complementary chi-square analyses, although these tests were not applied or reported in many of the original studies. The results showed that parasitoid diversity, abundance, and parasitism varied according to substrate type, host availability, and environmental conditions. Parasitoids are key regulators of insect populations, particularly those associated with decomposing organic matter and synanthropic environments. This study analyzed parasitoid–Diptera interactions across different environments and substrates, with emphasis on parasitism patterns, species diversity, host associations, and ecological relationships. Data were compiled from experimental studies conducted in Brazil, including forest, urban, pasture, livestock, and agricultural systems. Sampling methods included baited traps, exposure of organic substrates, recovery of pupae, and laboratory emergence of Diptera and parasitoids. Parasitism rates were standardized to allow comparisons among studies. In addition, the quantitative data available in several articles enabled complementary chi-square analyses, although these tests were not applied or reported in many of the original studies. The results showed that parasitoid diversity, abundance, and parasitism varied according to substrate type, host availability, and environmental conditions. Parasitoids such as Aphaereta sp. (Hymenoptera: Braconidae), Nasonia vitripennis (Walker, 1836) (Hymenoptera: Pteromalidae), Pachycrepoideus vindemmiae (Rondani, 1875) (Hymenoptera: Pteromalidae), and Spalangia spp. (Hymenoptera: Pteromalidae) were frequently associated with synanthropic Diptera, including Chrysomya albiceps (Wiedemann, 1819) (Diptera: Calliphoridae), Musca domestica L., 1758 (Diptera: Muscidae), and Peckia chrysostoma (Wiedemann, 1830) (Diptera: Sarcophagidae). Higher parasitoid activity was observed in environments rich in decomposing organic matter, especially animal feces, carcasses, poultry manure, and organic waste. Both generalist and more specialized parasitoids were recorded, indicating different ecological strategies and levels of host specificity. Overall, the findings highlight the ecological importance of parasitoids as natural enemies of Diptera and support their potential application in biological control programs. The complementary statistical analyses strengthened the interpretation of patterns previously described mainly in descriptive terms.