PurposeThe purpose of this study was to identify sex differences in postoperative outcomes and return‐to‐sport rates after fasciotomy for treatment of chronic exertional compartment syndrome (CECS) of the lower leg. It was hypothesised that male CECS patients would have a higher rate of return to sport than female CECS patients.MethodsA retrospective cohort study was conducted involving patients who underwent primary fasciotomy of one to four leg compartments for treatment of CECS at a single centre from 2010 to 2020. Each affected leg was treated as a separate subject. Postoperative outcomes included CECS pain frequency and severity, return to sport and Tegner activity level. Multivariable regression was used to determine if sex was an independent predictor of outcomes after adjusting for demographic and clinical covariates. p < 0.05 were considered significant.ResultsEighty‐one legs (44 M, 37 F) of 47 unique patients (34 of whom had bilateral symptoms) were included with a mean follow‐up time of 51.5 ± 31.4 months. Male subjects were older (p < 0.001) and had higher body mass index (p < 0.001) compared to female subjects. Most subjects (84.0%) underwent two‐ or four‐compartment fasciotomies. Female sex was found to be predictive of lower overall postoperative pain severity (p = 0.007), higher odds of return to sport (p = 0.04) and higher postoperative Tegner score (p = 0.005). However, female sex was not predictive of postoperative pain frequency, odds of reoperation or odds of return to sport to at least the presymptomatic level (all p < 0.05).ConclusionFemale sex is independently predictive of reduced overall pain severity, higher odds of return to sport and higher postoperative improvement in Tegner score following fasciotomy for treatment of lower‐limb CECS.Level of EvidenceIII.