The Conners 4–Short was developed according to best practices, with careful consideration given to evaluating the content, psychometric properties, and balance of the selected items. Shortened forms were created for Parent, Teacher, and Self-Report, and standard scores were calculated based on the Conners 4 Normative Samples and ADHD Reference Samples. The Conners 4–Short mirrors the full-length Conners 4 in terms of replicating the factor structure and retaining a high precision of measurement. The psychometric properties of the Conners 4–Short were investigated, and results meet or exceed guidelines for evidence related to reliability, validity, and fairness. Scores were stable across multiple administrations and multiple raters, while differing for raters with different perspectives. Profiles were measurably different in meaningful ways for individuals with ADHD, relative to those from the General Population. Finally, there was a lack of evidence for measurement bias for demographic subgroups, with negligible to small differences in mean scores, to support the generalizability of the test.