Background <p>Diabetic ketoacidosis (DKA) is a life-threatening complication requiring rapid assessment and specialized nursing. This study evaluated a virtual reality (VR) simulation program grounded in Kolb’s experiential learning theory to enhance nursing students’ DKA care competencies.</p> Methods <p>A randomized controlled trial was conducted with 44 nursing students (experimental: <i>n</i> = 22, control: <i>n</i> = 22) recruited via convenience sampling at a university in Korea. Participants were assigned using simple randomization. The primary outcomes were problem-solving ability and performance confidence; secondary outcomes included class evaluation, simulation design evaluation, and practice immersion. The experimental group received a VR-based program (lecture, VR, PBL, debriefing), while the control group engaged in e-book-based case simulation. The intervention was explicitly designed based on the four stages of Kolb’s experiential learning theory.</p> Results <p>There were significant interaction effects between group and time for primary outcomes, indicating the experimental group had significantly greater improvements in problem-solving ability (F = 11.51, <i>p</i> = .002) and performance confidence (F = 4.87, <i>p</i> = .033) compared to the control group. For secondary outcomes, the experimental group scored significantly higher in class evaluation (t = 5.60, <i>p</i> &lt; .001), simulation design evaluation (t = 5.88, <i>p</i> &lt; .001), and practice immersion (t = 3.612, <i>p</i> = .001).</p> Conclusion <p>The VR simulation program based on experiential learning theory was superior to e-book-based case simulation in enhancing students’ problem-solving skills and clinical confidence in DKA care. These findings support integrating VR simulation into nursing curricula as a superior pedagogical strategy to improve clinical readiness.</p>