This article reports the construction and validation of a comprehensive self-report measure of fantasy. Unlike previous measures of fantasy, which focus on psychopathology, we conceive fantasy as a trait with positive connotation. Principal component analysis (N = 318) and confirmatory factor analyses (N = 345) were conducted using 2 sociodemographically diverse samples. The results provided support for a 2-factor conceptualization of the construct, with the dimensions imaginative fantasy and creative fantasy. Imaginative fantasy refers to vivid imagination and absorption in these images and daydreams. Creative fantasy refers to the activity of using fantasy to create new ideas. The trait measure showed good internal consistency, test-retest reliability, discriminant and convergent construct validity, as well as incremental validity. Moreover, in 3 behavioral studies, we put fantasy scores in relationship with behavioral data to provide further proof of validity. A comprehensive measure of fantasy can contribute to our understanding of individual differences in inner experiences, creative processes, and problem solving.