Pediatric firearm injuries are a serious and growing public health problem, constituting the second leading cause of death in children and adolescents in the United States. Firearm injuries have a high case fatality, but knowledge is limited to date regarding their injury severity and health care utilization burden compared with those of other penetrating injuries, especially among children with critical injury. To describe and compare the resource utilization, injury severity, and short-term clinical outcomes associated with pediatric firearm injuries and other penetrating trauma. This retrospective cohort study used data from the National Trauma Data Bank, an encounter-level registry of trauma data in the United States, from January 1, 2007, to December 31, 2016. Encounters for firearm injury (n = 25 155) or cut or pierce injury (21 270) in children 17 years or younger were analyzed. Statistical analysis was conducted from July 15, 2018, to June 5, 2019. Firearm injury compared with cut or pierce injury encounters. Intensive care unit (ICU) admission, hospital and ICU length of stay (LOS), and Injury Severity Score (ISS). A total of 25 155 firearm injury encounters and 21 270 cut or pierce injury encounters were analyzed. Most firearm and cut or pierce injuries occurred among boys (21 573 [85.8%] and 15 864 [74.6%]) and adolescents aged 15 to 17 years (18 807 [74.8%] and 10 895 [51.2%]). A greater proportion of those with firearm injuries were African American children compared with those with cut or pierce injuries (15 019 [61.3%] vs 6397 [31.2%]). A greater proportion of those with firearm injuries compared with cut or pierce injuries were admitted to the ICU (7682 [30.5%] vs 2712 [12.8%]). Compared with cut or pierce injuries, firearm injuries were associated with a higher mean (SD) ISS (4.6 [6.8] vs 10.9 [12.7] points), longer mean (SD) hospital LOS (2.8 [4.1] vs 5.0 [8.4] days), and longer mean (SD) ICU LOS (3.1 [4.5] vs 5.1 [7.7] days). Firearm injuries accounted for 126 027 hospital days and 39 255 ICU days, whereas cut or pierce injuries accounted for 58 705 hospital days and 8353 ICU days. After adjustments for age, sex, year, and hospital, those with firearm injuries were more likely to require ICU admission (relative risk [RR], 2.3; 95% CI, 2.1-2.5; P < .001) and to have higher ISS scores (6.7 points higher for all injuries; 95% CI, 6.1-7.2) compared with those with cut or pierce injuries, even among critical injuries. Multinomial logistic regression demonstrated higher risk of prolonged hospital LOS (RR ratio, 4.11; 95% CI, 3.46-4.89; P < .001) and ICU LOS (RR ratio, 2.2; 95% CI, 1.9-2.3) for firearm injuries compared with cut or pierce injuries. This study found that pediatric firearm injuries were associated with greater severity and health care utilization compared with penetrating trauma from other mechanisms, suggesting that the mechanism of injury is an important consideration in penetrating sharp force trauma in children and adolescents. Public health measures, legislative efforts, and safe storage practices are among the interventions needed to reduce pediatric firearm injuries.