The standard therapeutic approach for patients with head and neck cancer (HNC) often involves multi-modality therapy including surgery, radiation therapy (RT) or chemoradiation therapy (CRT). Treatment complications include mucositis, weight loss, and feeding tube dependence (FTD) which can result in treatment delays, incomplete treatment, and decreased quality of life (QOL). Recent studies on the effects of photobiomodulation therapy (PBMLT) have demonstrated promising reductions in severity of mucositis but there is a lack of quantitative data demonstrating these effects. In addition, there are few studies evaluating the effect that PBMLT has on other parameters such as weight loss and FTD. We conducted a matched case-control study comparing treatment complications for patients with HNC receiving PBMLT to those who did not, hypothesizing that PBMLT improves mucositis severity, weight loss and FTD.Medical records of 44 patients with HNC treated with CRT or RT at a single institution from 2015-2021 were retrospectively reviewed. Twenty-two patients received PBMLT and were matched 1:1 to controls based on age, RT fields, and RT dose. Outcomes included maximum mucositis grade per CTCAE v5.0, weight loss as a percentage of pre-treatment weight, and FTD 100 days after initiation RT or CRT. Outcomes were compared between groups by conducting various statistical tests, including Wilcoxon Rank Sum for weight loss, Fisher's Exact test for FTD at 100 days, and Chi Square for maximum mucositis grade.Of 44 patients, the median age was 63.5 years (IQR 12.5). Median RT dose was 60 Gy in the PBMLT group and 66 Gy in the control group. Of patients treated with PBMLT, 11 received CRT and 11 received RT alone. Of control patients, 16 received CRT and 6 received RT alone. For patients in the PBMLT group, the median number of PBMLT treatment sessions was 22 (IQR 6.75). The median maximal mucositis grade was 2 in the PBMLT group compared to 3 in the control group, which was statistically significant (P = 0.0016). The median percent weight loss for PBM patients was 6.7% compared to 7.3% in the control group which was not statistically significant (P = 0.35). Nine patients in the control group required FT placement during RT or CRT, compared to 5 patients in the PBMLT group. The odds ratio of requiring a FT to be placed during treatment for patients receiving PBMLT was 0.385 (95% CI, 0.165 to 0.896).This study demonstrates that PBMLT may have a role in decreasing complications related to RT and CRT for HNC, mainly mucositis severity. There is also likely benefit in decreasing the rate feeding tube placement during RT or CRT. We conclude that PBMLT has the potential to improve patient adherence to therapy, safety, and QOL during cancer treatment.