The role of age in mediating coagulation characteristics in injured children is not well defined. We hypothesize thromboelastography (TEG) profiles are unique across pediatric age groups. Consecutive trauma patients younger than 18 years from a Level I pediatric trauma center database from 2016 to 2020 with TEG obtained on arrival to the trauma bay were identified. Children were categorized by age according to the National Institute of Child Health and Human Development categories (infant, ≤1 year; toddler, 1-2 years; early childhood, 3-5 years; older childhood, 6-11 years; adolescent, 12-17 years). Thromboelastography values were compared across age groups using Kruskal-Wallis and Dunn's tests. Analysis of covariance was performed controlling for sex, Injury Severity Score (ISS), arrival Glasgow Coma Scale (GCS) score, shock, and mechanism of injury. In total, 726 subjects were identified; 69% male, median (interquartile range IQR) ISS = 12 (5-25), and 83% had a blunt mechanism. On univariate analysis, there were significant differences in TEG α-angle ( p < 0.001), MA ( p = 0.004), and fibrinolysis 30 minutes after MA (LY30) ( p = 0.01) between groups. In post hoc tests, the infant group had significantly greater α-angle (median, 77; IQR, 71-79) and MA (median, 64; IQR, 59-70) compared with other groups, while the adolescent group had significantly lower α-angle (median, 71; IQR, 67-74), MA (median, 60; IQR, 56-64), and LY30 (median, 0.8; IQR, 0.2-1.9) compared with other groups. There were no significant differences between toddler, early childhood, and middle childhood groups. On multivariate analysis, the relationship between age group and TEG values (α-angle, MA, and LY30) persisted after controlling for sex, ISS, GCS, shock, and mechanism of injury. Age-associated differences in TEG profiles across pediatric age groups exist. Further pediatric-specific research is required to assess whether the unique profiles at extremes of childhood translate to differential clinical outcomes or responses to therapies in injured children. Prognostic and Epidemiological; Level IV.