Suicide and homicide are the second and third leading causes of death, respectively, among youths aged 14-17 years (1); nearly one half (46%) of youth suicides and most (93%) youth homicides result from firearm injuries (1). Understanding youth gun carrying and associated outcomes can guide prevention initiatives (2). This study used the updated measure of gun carrying in the 2017 and 2019 administrations of CDC's Youth Risk Behavior Survey* (YRBS) to describe the national prevalence of gun carrying for reasons other than hunting or sport among high school students aged <18 years and to examine the associations between gun carrying and experiencing violence, suicidal ideation or attempts, or substance use. Gun carrying during the previous 12 months was reported by one in 15 males and one in 50 females. Gun carrying was significantly more likely among youths with violence-related experiences (adjusted prevalence ratio [aPR] range = 1.5-10.1), suicidal ideation or attempts (aPR range = 1.8-3.5), or substance use (aPR range = 4.2-5.6). These results underscore the importance of comprehensive approaches to preventing youth violence and suicide, including strategies that focus on preventing youth substance use and gun carrying (3).