Evidence that an instrument measures what it purports to measure is essential to empirically study the given construct. Despite this fact, little attention has been made to investigate the validity of the Inventory of Childhood Memories and Imaginings (ICMI) and the Creative Experiences Questionnaires (CEQ) - instruments that purport to measure the fantasy proneness construct. In assessing the validity of fantasy proneness measures, the aim of the current study was unique, in that, no known study had conducted a factor analysis of scores on the ICMI, CEQ and Dissociative Experiences Scale (DES) separately and simultaneously in the same study. Undergraduate psychology students (N = 223) from a large New Zealand University completed six questionnaires measuring fantasy proneness, imagery, dissociation, personality and desirable responding. Separate factor analysis results suggested a three factor solution for ICMI scores accounting for 22.60% of the total variance, a six factor solution for CEQ scores accounting for 42.93% of the total variance, and a three factor solution for DES scores accounting for 81.31% of the total variance. Simultaneous factor analysis results on factor scores of the ICMI, CEQ and DES revealed that dimensions of fantasy proneness loaded on two factors, whereas dimensions of dissociation loaded distinctively on a separate factor. The findings from this study suggest that there is less dimensional overlap between fantasy proneness and dissociation than has been suggested in the recent literature. Findings of this study also suggest that conclusions based on the overall scales of fantasy proneness may be limited and potentially misleading.