Background: Body weight affects outcomes of surgical treatment for various conditions, but its effects on the treatment of neurogenic thoracic outlet syndrome (NTOS) are unknown. The purpose of this study was to evaluate the influence of body weight on technical and functional outcomes of surgical treatment for NTOS. Methods: A retrospective review of prospectively collected data was conducted for 265 patients who underwent supraclavicular decompression for NTOS between January 1, 2014 and March 31, 2016. Patients were grouped according to 6 standard body mass index (BMI) categories. The influence of BMI on measures of surgical outcome was analyzed using Pearson correlation statistics, analysis of variance (ANOVA), and multivariate logistic regression. Results: Mean patient age was 33.3 ± 0.7 years (range, 12–70), and 208 (78%) patients were women. Mean BMI was 27.2 ± 0.4 (range 16.8–49.9), with 7 underweight (3%), 95 normal (36%), 84 overweight (32%), 47 obese-I (18%), 15 obese-II (6%), and 17 obese-III (6%). There was a slight but significant association between BMI and age (Pearson P < 0.0001, r = 0.264; ANOVA P = 0.0002), but no correlations between BMI and other preoperative variables. There were no differences between BMI groups for intraoperative, immediate postoperative, or 3-month outcomes. Multivariate logistic regression demonstrated that BMI had no significant effect on functional outcome as measured by the extent of improvement in Disability of the Arm, Shoulder, and Hand score at 3 months (P = 0.429). Conclusions: There was no substantive influence of BMI on preoperative characteristics or intraoperative, postoperative, or 3-month outcomes for patients with NTOS, and no indication of an “obesity paradox” for this condition. Supraclavicular decompression for NTOS achieves similar outcomes across the BMI spectrum.