Maladaptive daydreaming (MD) is an extensive fantasy activity that replaces human interaction and interferes with work and interpersonal functioning. In this study, we investigated the nomological network of the MD construct and examined the psychometric properties of the Maladaptive Daydreaming Scale (MDS-16) in an Italian sample. The MDS-16 is a self-report measure composed of 16 items designed to assess MD. Participants in this study were 468 individuals (333 volunteers, 56.8% female; 135 self-diagnosed maladaptive daydreamers, 78.5% female) between 18 and 56 years of age. MDS-16 scores showed good internal reliability. An exploratory factor analysis suggested a 2-factor solution (interference with life and sensory-motor retreat); this solution was consistent with theory, and all items loaded in the expected direction. MDS-16 scores were associated with global psychopathology, traumatic experiences, maladaptive personality features, alexithymia, dissociation, shame feelings, and anxious attachment styles. Furthermore, MDS-16 scores showed satisfactory incremental validity, and a receiver operating characteristic curve analysis suggested that a cutoff value of 51 best discriminates between cases and noncases of self-diagnosed MD. Results suggest that the scale is a suitable measure for assessing MD in Italian samples.