["Journal of Clinical Psychology, EarlyView. ", "\nABSTRACT\n\nObjective\nThe validity and psychometric qualities of the Difficulties in Emotion Regulation Scale (DERS) in populations with a broader range of personality disorders (PDs) are still unclear. The aim of the current study was to analyze the factor structure and validity of DERS and two of its short‐forms (DERS‐SF and DERS‐18), their relation to PD features and personality functioning, gender differences, and the overlap between concepts of alexithymia and emotion regulation.\n\n\nMethod\nData were extracted from a multi‐site clinical sample of patients with PDs or personality related problems referred to specialist mental health services (n = 2093). Confirmatory factor analyses (CFA)—specifically first‐order correlated and bifactor analysis, as well as analysis of measurement invariance—were applied. Linear associations and group differences were investigated by correlational analysis and independent samples t‐tests. DERS and its shortforms were validated through associations with PD features (PD criteria), measures of personality functioning (LPFS‐BF), and alexithymia (TAS‐20).\n\n\nResults\nCFA of the short forms revealed good model fit, while the full version of DERS showed poorer fit. None of the bifactor analyses supported a strong general factor. Gender differences were prominent, and substantial associations were found between DERS and PD criteria, LPFS‐BF, and TAS‐20.\n\n\nConclusion\nDERS and its short forms demonstrated acceptable reliability and validity in a sample of patients with PDs and personality related problems. Without support for a general factor, interpretation of the total scores of DERS should be conducted with care, especially if the subscales Awareness and Clarity are included. Given the advantages of the short forms, the selection of one version over another seems to be of limited consequence.\n"]