The purpose of the study was to explore why individuals dress in costume. From a symbolic interactionist perspective, the study extends Stone's theory of adultfantastic socialization and Eicher's framework of dress and the public, private, and secret self. The study also introduces the concept of afantasy‐prone personality within the study of dress. The Dressingfor Fun and Fantasy Questionnaire was developed and administered to 216 individuals who dress in costume. Data were analyzed using qualitative, quantitative, and critical analyses approaches. Data analyzedfor this study include reasonsfor interest in costuming (via checklistformat) and respondents' written comments to an open‐ended question. Results indicate thatfemales dress in costume primarily to assume another persona, whereas males dress in costume primarily because oftheir love of history. Theoretical explanations are given, an expansion of Eicher's model is proposed, and recommendations are madeforfuture study.