The Difficulties in Emotion Regulation Scale (DERS) is a measure of emotion regulation that has been extensively used in research and clinical settings, both with adolescents and adults. However, its length has been recognized as an important limitation. In addition, its adequacy as a multidimensional measure and the utility and interpretability of the Awareness subscale has been questioned. The goal of this study is to contribute to the clarification of these issues through the examination of the factor structure and psychometric properties of a short form of the DERS in a large sample of Portuguese adolescents and adults from the community. Two studies were conducted. The first study comprised 1314 adults and the second study comprised 612 adolescents, who completed the DERS-SF and additional measures to assess validity evidence for DERS-SF scores in relation to other relevant variables (self-compassion, attachment orientations, anxiety and depressive symptoms, dispositional mindfulness, perceived stress, emotion suppression, and quality of life). Several models were examined in two studies as well as bifactor model-based psychometric indices. In both studies, bifactor models, particularly the one that excluded the Awareness items, exhibited a good fit to the data. ECV and OmegaH indices suggest a strong general factor of emotion dysregulation and do not support individual use of the Objectives, Strategies, Impulse, and Nonacceptance subscales. The DERS-SF scores correlated with the other measures as expected. Our findings suggest that the Awareness subscale should be excluded when computing the DERS-SF total score and that the total score can be considered essentially unidimensional. This study supports the use of a total score to assess emotion dysregulation but does not support the use of most subscale scores.