BackgroundIn the evolutionary study of gene families, exploring the duplication mechanisms of gene families helps researchers understand their evolutionary history. The tubby-like protein (TLP) family is essential for growth and development in plants and animals. Much research has been done on its function; however, limited information is available with regard to the evolution of theTLPgene family. Herein, we systematically investigated the evolution ofTLPgenes in seven representative Poaceae lineages.ResultsOur research showed that the evolution ofTLPgenes was influenced not only by whole-genome duplication (WGD) and dispersed duplication (DSD) but also by transposed duplication (TRD), which has been neglected in previous research. ForTLPfamily size, we found an evolutionary pattern of progressive shrinking in the grass family. Furthermore, the evolution of theTLPgene family was at least affected by evolutionary driving forces such as duplication, purifying selection, and base mutations.ConclusionsThis study presents the first comprehensive evolutionary analysis of theTLPgene family in grasses. We demonstrated that theTLPgene family is also influenced by a transposed duplication mechanism. Several new insights into the evolution of theTLPgene family are presented. This work provides a good reference for studying gene evolution and the origin of duplication.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12864-023-09389-z.