Purpose <p>To compare the incidence of radiation-induced temporal lobe injury (TLI) between helical tomotherapy (HT) and conventional intensity-modulated radiotherapy (IMRT) in patients with nasopharyngeal carcinoma (NPC).</p> Methods <p>We retrospectively reviewed the medical records of NPC patients who underwent curative-intent HT or IMRT from March 2015 to December 2020 at our institution. Propensity score matching (1:1) was performed to minimize the impact of potential confounders. TLI was diagnosed based on the magnetic resonance imaging (MRI) findings. The actuarial rates of TLI were analysed by the Kaplan-Meier method and log-rank test. Univariate and multivariate analyses were used to determine prognostic factors for TLI.</p> Results <p>837 patients were included, of which 422 were treated with IMRT and 415 with HT. After matching, 286 patients in each group were successfully matched. The median follow-up time was 47.57 months (IQR, 37.06–58.81 months) and 46.28 months (IQR, 37.14–57.02 months) for the IMRT and HT groups, respectively. The crude incidence of TLI was 19.2% and 11.2% (<i>P</i> = 0.010), and the 5-year actuarial rate of TLI was 31.7% and 18.1% for the IMRT and HT groups (<i>P</i> = 0.011), respectively. Multivariate analysis showed that radiotherapy technique, age, sex, T stage, GTV, Dmax, D2cc, D1cc, D0.5&#xa0;cc, V60 and V65 of bilateral temporal lobes (TL) were independent predictors for TLI (all <i>P</i> &lt; 0.05).</p> Conclusion <p>Reduced irradiated TL volumes and doses of HT consequently reduced incidence and severity of TLI compared to IMRT. In addition, Dmax, D2cc, D1cc, D0.5&#xa0;cc, V60, and V65 of TL contributed to the TLI.</p> Clinical trial number <p>Not applicable.</p>