ABSTRACT: Importance:Effective postoperative pain management increases patient satisfaction, reduces cost, reduces morbidity, and shortens hospitalizations. Previous studies investigating multimodal pain therapy in otolaryngology patients focused on homogenous patient groups with short postoperative follow-up times. Objective:To investigate the effect of perioperative gabapentin treatment on postsurgical pain in patients undergoing head and neck mucosal surgery. Design, Setting, and Participants:Adults undergoing head and neck mucosal surgery from July 25, 2016, through June 19, 2017, were included in this double-blinded, placebo-controlled randomized clinical trial and randomized to receive gabapentin, 300 mg twice daily, or placebo before surgery and up to 72 hours after surgery. Main Outcomes and Measures:Primary outcome was hourly narcotic use calculated in morphine equivalents. Secondary outcomes included subjective visual analog scale pain scores captured for resting, coughing, and swallowing using a 0- to 100-mm scale (a 100-mm line anchored with no pain on the left end and worst possible pain on the right end). A change of 10 mm or more was deemed to be clinically meaningful. Additional secondary outcome measures included degree of pain control, patient satisfaction, and adverse effects. Results:Of the 110 patients randomized to receive gabapentin or placebo, 11 and 10 withdrew from each group, respectively. Ninety patients were then analyzed: 44 in the gabapentin group (mean [SD] age, 61.1 [10.0] years; 33 [75%] male; 40 [91%] white) and 46 in the placebo group (mean [SD] age, 60.9 [11.3] years; 35 [78%] male; 43 [94%] white). Both groups had similar self-reported levels of preoperative pain and narcotic effectiveness. A median difference of 0.26 mg/h of morphine (95% CI, -0.27 to 0.94 mg/h) was found between groups. After controlling for comorbidity and self-reported baseline pain levels, mixed model analysis found the difference in marginal means of visual analog scale scores between groups to be lower in the gabapentin group compared with the placebo group for all categories (rest difference, 7.9 mm; 95% CI, -0.4 to 16.2 mm; cough difference, 8.9 mm; 95% CI, -0.5 to 18.3 mm; swallow difference, 9.4 mm; 95% CI, -1.2 to 20.0 mm). More patients in the gabapentin group reported that pain was always well controlled than in the placebo group (difference, 9.2%; 95% CI, -21% to 3%). Gabapentin and placebo groups reported similar levels of satisfaction with pain control (difference, 2%; 95% CI, -11% to 15%). There was no clinically meaningful difference in reported nausea between the 2 groups (difference, 6%; 95% CI, -14% to 26%). Conclusion and Relevance:Perioperative gabapentin given 300 mg twice daily did not result in reduced narcotic use, but results were compatible with clinically meaningful reductions in pain scores. Satisfaction with pain control and adverse effects were similar between groups. Trial Registration:ClinicalTrials.gov Identifier: NCT02926573.