Contrary to longstanding arguments that equate parties with durable, information-rich brand names, the relabeling of parties is not rare, and in many countries it is not even very unusual. This paper provides the first effort to document this neglected phenomenon. It finds that across European democracies roughly a third of all parties have relabeled themselves at least once since 1945, and a similar proportion of elections include at least one party running under a new name. It then presents analyses of why parties change names more frequently in some circumstances, finding support for three explanations derived from the existing literature: parties with longer-standing brands are less likely to shed them, but relabeling is more likely for parties that suffer electoral setbacks and for parties in weaker party systems. Finally, it presents evidence that the end of Soviet communism made left parties more likely to rename themselves.