Impulsivity contributes to many clinically relevant behaviors impacting youth. A scoping review was conducted to characterize existing research using the Urgency, Premeditation (lack of), Perseverance (lack of), Sensation Seeking (UPPS) Impulsive Behavior Scales in youth populations, to review the psychometric and validity data of UPPS, and to summarize findings related to sex/gender and diagnostic populations of youth. PubMed, Embase, and PsycNET databases were searched from January 1, 2001 (original UPPS publication) through October 2, 2022, according to PRISMA extension for Scoping Reviews guidelines. Articles were reviewed for inclusion/exclusion by 2 authors. Original research articles in English using any UPPS version or subscale in persons aged ≤21 years were included. Inclusion criteria were met by 45 articles, with low bias and moderate-to-high quality. Most were cross-sectional studies; studies investigated diverse community and clinical samples. The UPPS demonstrated consistent factor structure, good reliability, and good external validity with other measures of impulsive behaviors and conditions associated with impaired impulse control. Some studies observed differences in UPPS domain scores between sex/gender groups or differential patterns in relationships between UPPS domains and clinical variables. UPPS subscale scores often differed in youth with attention-deficit/hyperactivity disorder, conduct disorders, substance use, and excess weight/obesity compared with control youth. UPPS domains commonly had interactions with sex/gender, sociodemographic, and diagnosis-related variables. The current literature suggests that the UPPS has utility in measuring distinct components of impulsivity in clinical and nonclinical populations of youth. Specificity in discriminating diagnostic groups and predicting risk currently remains uncertain. Further research is needed to integrate UPPS measures with experimental models and additional neurobiological methods and to assess longitudinal developmental trajectories. Impulsivity contributes to many clinically relevant behaviors and mental health disorders that impact youth. The Urgency, Premeditation, Perseverance, Sensation Seeking (UPPS) Impulsive Behavior Scale has been increasingly used in research to measure deficits in impulse control. In this scoping review the authors examined 45 studies that used versions of the UPPS to measure different domains of impulsivity in youth aged 21 years and younger. The authors found evidence in the literature for the validity and reliability of the UPPS and its variants in measuring impulsivity in youth. Certain patterns of UPPS subscale scores corresponded with clinical behaviors and diagnoses including attention-deficit/hyperactivity disorder (ADHD), conduct disorder, substance use, and excessive weight/obesity. Despite this, there remain gaps in the literature regarding the stability of UPPS measures over time and ability of the UPPS to predict clinical outcomes. [ABSTRACT FROM AUTHOR] more...