Different studies have provided evidence that adverse childhood experiences (ACEs) are associated with mental health problems as a function of racial and ethnic diversity. The aim of the present study was thus to study the association between ACEs and dissociation in a sample of Southern Italian public psychology service (PPS) users. A sample of 183 adults who requested psychotherapeutic treatment within an Italian PPS was recruited. ACEs were assessed via the Adverse Childhood Experiences Questionnaire (ACE-Q). Dissociative symptoms were assessed via the Dissociative Experiences Scale (DES-II) and the Somatoform Dissociation Questionnaire (SDQ-20). Dissociative syndromes were assessed via two scales of the Millon Clinical Multiaxial Inventory (MCMI-III): the Somatoform Syndrome (H) and the Post-Traumatic Stress Disorder Syndrome (R) scales. The most common types of ACEs in our sample were emotional neglect and emotional abuse. The number of ACEs showed a significant association with all the different measures of dissociation administered. Logistic regression analysis for the DES-II resulted in a solution made up of sexual abuse and parental separation or divorce. The regression analysis for the SDQ-20 resulted in a solution made up of emotional abuse, physical neglect, and parental separation or divorce. Sexual abuse positively predicted PTSD scale scores, while no solution was found for somatoform disorder. ACEs and dissociation were strongly associated in this study, but the nature of this association depended on the aspect of dissociation under investigation, particularly when we considered the distinction between dissociative symptoms versus syndromes. Cultural characteristics and clinical implications for public services are discussed.