Debate exists in the trauma literature regarding the role of dissociation in traumatic stress disorders. With the release of the new ICD-11 diagnostic guideline for posttraumatic stress disorder (PTSD) and complex PTSD (CPTSD), this issue warrants further attention. In the current study, we provide a preliminary assessment of the associations between ICD-11 CPTSD and dissociative experiences. This study is based on a sample (N = 106) of highly traumatized clinical patients from the United Kingdom who completed measures of traumatic stress and dissociative experiences. The majority of participants met the diagnostic criteria for CPTSD (69.1%, n = 67), with few patients qualifying for a diagnosis of PTSD (9.3%, n = 9). Those with CPTSD had significantly higher levels of dissociative experiences compared to those with PTSD (Cohen’s d = 1.04) and those with no diagnosis (Cohen’s d = 1.44). Three CPTSD symptom clusters were multivariately associated with dissociation: Affective Dysregulation (β = .33), Reexperiencing in the here and now (β = .24), and Disturbed Relationships (β = .22). These findings indicate that dissociative experiences are particularly relevant for clinical patients with CPTSD. Future longitudinal work will be needed to determine if dissociation is a risk factor for, or outcome of, CPTSD.