Steroidal glycoalkaloids (SGAs) are cholesterol derivatives that effectively protect plants from pathogens and pests. They are mainly found in Solanum Plants and are synthesized in actively growing and young tissues. Their biosynthesis occurs in three stages: cholesterol biosynthesis, conversion of cholesterol to steroidal alkaloids, and glycosylation of these alkaloids. The biosynthesis of SGAs in Solanum Plants is influenced by genetics, transcription factors, and light signaling. Currently, research on the distribution, types, synthesis, and genetics of SGAs is a major focus of scholars worldwide. This review integrates recent research advancements, summarizing the key genes controlling SGAs biosynthesis in Solanum Plants (HMGR, SQS, SSR2, SGT2, GAME1, GAME2, GAME17GAME4, GAME18GAME6, GAME4GAME7, GAME6GAME8, GAME7GAME11, GAME8GAME12, GAME15, GAME11GAME17, and GAME12GAME18), the main differential genes between wild and cultivated species (GAME5、GAME25, S5αR2, GAME31 and GAME32), the regulation of SGAs biosynthesis by hormone-related transcription factors (GAME9, COI1 and TCP14), and the impact of light-responsive transcription factors (HY5, PIF3 and MYB113) and photosynthetic pigment enzymes (PDS, CHLI and CHLH) on SGAs biosynthesis. It also discusses future directions for SGA research in Solanum Plants.