Background: This study aimed to examine the correlation between early-phase lactate, albumin, and lactate-to-albumin ratio (LAR) measurements and mortality in pediatric trauma patients. Methods: A retrospective analysis was conducted on pediatric patients with severe trauma who received treatment in the Pediatric Intensive Care Unit (PICU). We collected demographic characteristics, serum lactate and albumin levels at admission, type of trauma (falls from height, traffic accidents), medical interventions, and imaging methods performed before and after intensive care admission. The Glasgow Coma Score (GCS), Pediatric Risk of Mortality Score III (PRISM III), Pediatric Death Rate (PDR), Pediatric Trauma Score (PTS), and mortality outcomes were also documented. Results: A total of 184 pediatric severe trauma patients were included in this retrospective cohort study and categorized into survivors and non-survivors. The median (interquartile range (IQR)) age of survivors was 87.5 (16.25–100.50) months, while the median (IQR) age of non-survivors was 71.5 (30.75–92.75) months. Lactate, albumin, and the LAR were included in separate models, given that LAR is derived from lactate and albumin values. The regression analysis revealed that PRISM III and lactate (Odds Ratio (OR): 1.6, 95% Confidence Interval (CI) (1.03–2.62); p = 0.039) were independent risk factors for mortality in trauma patients. In the regression model, the LAR value was selected through the forward selection process, meeting the significance threshold (OR: 4.63, 95% CI (0.99–21.60); p = 0.05). Conclusions: LAR may serve as a valuable adjunct to other risk assessment tools in pediatric trauma patients. Its use could facilitate the early identification of patients at higher risk of mortality, thereby enhancing clinical decision-making and improving patient outcomes.