This article presents an evolution of transfer of training from 1901 to 2020. The discussion about transfer of training begins with a brief introduction to the framework about the transfer process, followed by the literature review on transfer of training. For the purpose of simplicity, the literature review is broadly discussed based on three eras of research: 1901 to 1988, 1988 to 2008, and 2008 to 2020. During the entire discussion, the results of the research conducted in the three eras are compared and the changing research trends from 1901 to 2020 are discussed.