The CAARS 2–Short was developed according to best practices, with careful consideration to evaluating the content, psychometric properties, and balance of the selected items. Shortened forms were created for Self-Report and Observer, and standard scores were calculated based on the CAARS 2 Normative Sample and ADHD Reference Sample. The CAARS 2–Short Content Scales mirror the full-length CAARS 2 Content Scales in terms of replicating the factor structure and retaining a high precision of measurement. The psychometric properties of the CAARS 2–Short Content Scales meet or exceed guidelines for evidence related to reliability, validity, and fairness. Scores were stable across multiple administrations and multiple raters of the same type (such as two friends), while scores differed somewhat for raters of different types (such as a spouse and a sibling). CAARS 2–Short profiles for individuals with ADHD, individuals with Anxiety or Depression, and individuals from the General Population all differed in expected ways, lending strong evidence that the CAARS 2–Short corresponds as intended with external diagnostic criteria, and effectively classifies membership among these groups. Finally, there is substantial support for the fairness and generalizability of the CAARS 2–Short, as there was a lack of evidence of measurement bias for demographic subgroups, with negligible to small differences in mean scores among those subgroups.