PURPOSE: Clinical practice guidelines intended to reduce unnecessary cervical spine imaging have yielded mixed results. We aimed to assess evolving emergency department (ED) cervical spine imaging utilization in patients with trauma by injury severity. METHODS: Using 2009 to 2018 IBM MarketScan Commercial Databases, we identified ED trauma encounters, associated cervical spine imaging, and related diagnosis codes. We classified encounters by injury severity (minor, intermediate, major) using an International Classification of Disease code-derived Injury Severity Score algorithm and studied evolving imaging utilization using multivariable Poisson regression models. RESULTS: Of all 11,346,684 ED visits for trauma, 7,753,914 (68.3%), 3,524,250 (31.1%), and 68,520 (0.6%) involved minor, intermediate, and major injuries, respectively. Overall cervical spine imaging increased 5.7% annually (incidence rate ratio [IRR] 1.057, P < .001) with radiography decreasing 2.7% annually (IRR 0.973, P < .001) and CT increasing 10.5% annually (IRR 1.105, P < .001). Radiography utilization remained unchanged for minor injuries (IRR 0.994, P = .14) but decreased for intermediate (IRR 0.928 versus minor, P < .001) and major (IRR 0.931 versus minor, P < .001) injuries. Increases in CT utilization were greatest for minor injuries (IRR 1.109, P < .001) with smaller increases in intermediate (IRR 0.960 versus minor, P < .001) and major (IRR 0.987 versus minor, P = .022) injuries. CONCLUSIONS: Recent increases in cervical spine imaging in commercially insured patients with trauma seen in the ED have been largely related to increases in CT for patients with only minor injuries, in whom imaging utilization has been historically low. Further study is necessary to assess appropriateness, implications on costs and population radiation dose, and factors influencing ordering decision making.