Fantasy proneness refers to an extensive involvement in fantasy and daydreaming. Previous studies have shown that fantasy proneness overlaps with dissociative tendencies, as measured with the Dissociative Experiences Scale. We tested the hypothesis that deviant sleep experiences form the critical link between fantasy proneness and dissociation. Undergraduate students (N = 205) completed the Creative Experiences Questionnaire, the Dissociative Experiences Scale, and the Iowa Sleep Experiences Survey. Self-reports of sleep experiences, such as narcolepsy, vivid and unusual dreams, and deviant nocturnal experiences, but not lucid dreaming, were related to both fantasy proneness and dissociation. However, the relationship between fantasy proneness and dissociation was only partially accounted for by these sleep experiences. This suggests that deviant sleep experiences but also other, as yet unknown, factors contribute to the overlap between fantasy proneness and dissociation.