The expanded version of the Inventory of Depression and Anxiety Symptoms (IDAS-II) is a 99-item self-report measure containing 18 nonoverlapping dimensional scales assessing symptoms of depression, anxiety, and mania. The aim of this study was to develop and validate a German adaptation of the IDAS-II. Participants from a community sample (N = 1,054) completed the IDAS-II (German version). In addition, part of the sample (N = 550) completed a series of additional measures of depression (Patient Health Questionnaire-9, WHO-Five Well-Being Index, Symptom Checklist-90 Revised-Short Version) and anxiety disorders (Generalized Anxiety Disorder Scale-7, Fear of Negative Evaluation Scale-5, Dimensional Obsessive-Compulsive Scale, The International Trauma Questionnaire). We conducted item-level confirmatory factor analyses (CFA) separately for the 15 nonsaturated IDAS-II scales, which confirmed unidimensionality. McDonald's ω indicated good internal consistency (ω > .8) of all symptom scales except Euphoria (ω = .751) and Ordering (ω = .728). A CFA of the IDAS-II scales, based on exploratory results by Watson et al. (2012), confirmed a three-factor model of "Distress," "Obsessions/Fear," and "Positive Mood." Correlational analyses with additional symptom measures supported the convergent and discriminant validity of the IDAS-II scales. The IDAS-II (German version) allows for a reliable assessment of the severity of depression, anxiety, and bipolar symptoms and is one of the first clinical measures for German-speaking samples that is consistent with the Hierarchical Taxonomy of Psychopathology (HiTOP). (PsycInfo Database Record (c) 2022 APA, all rights reserved).