Since the term “gentrification” was coined by Ruth Glass in 1964, this concept and the phenomenon it referred to have been subject to change. This paper reviews the literature and employs Ian Hacking’s work to investigate how two types of changes—that is, changes of the concept and of the phenomenon—are implicated by each other. By investigating the interaction between a classification and its class, it becomes possible to understand gentrification as, in Hacking’s terms, a “moving target.” This paper argues that gentrification can be conceptualized as such and explores the consequences of this for gentrification research.