Oil cakes, valuable co-products of the oil industry, are rich in bioactive and nutritional compounds, making them suitable for biotechnological processes that lower costs and reduce environmental impact. These versatile materials are commonly used as substrates for microbial enzyme production, particularly in the context of sustainable, cost-effective protease synthesis. This review surveyed the application of oil cakes as substrates for microbial protease production, focusing on studies published between 2013 and 2023 from databases such as ScienceDirect, PubMed, Web of Science, and Scopus. After screening, 30 studies were deemed eligible from an initial pool of 1602 articles. Nineteen different oil cake types were identified, with soybean cake being the most utilized. The studies highlighted the effectiveness of oil cakes in supporting microbial protease production, particularly with species from the Aspergillus (fungi) and Bacillus (bacteria) genera. Despite the diversity of microorganisms and substrates explored, only a limited number of studies provided detailed compositional analyses of the oil cakes. Nonetheless, the review underscores the growing trend of using oil cakes as an economical and sustainable nutrient source for microbial protease production. Oil cakes, valuable co-products of the oil industry, are rich in bioactive and nutritional compounds, making them suitable for biotechnological processes that lower costs and reduce environmental impact. These versatile materials are commonly used as substrates for microbial enzyme production, particularly in the context of sustainable, cost-effective protease synthesis. This review surveyed the application of oil cakes as substrates for microbial protease production, focusing on studies published between 2013 and 2023 from databases such as ScienceDirect, PubMed, Web of Science, and Scopus. After screening, 30 studies were deemed eligible from an initial pool of 1602 articles. Nineteen different oil cake types were identified, with soybean cake being the most utilized. The studies highlighted the effectiveness of oil cakes in supporting microbial protease production, particularly with species from the Aspergillus (fungi) and Bacillus (bacteria) genera. Despite the diversity of microorganisms and substrates explored, only a limited number of studies provided detailed compositional analyses of the oil cakes. Nonetheless, the review underscores the growing trend of using oil cakes as an economical and sustainable nutrient source for microbial protease production.