Aim: The aim of this study was to retrospectively analyze changes in age- and sex-adjusted body mass index (BMI) in ambulatory children with cerebral palsy (CP) who underwent selective dorsal rhizotomy (SDR). Method: Raw BMI, age- and sex-adjusted BMI z-scores, weight classification status, energy expenditure, and ambulation function were calculated before and after SDR at multiple post-SDR time points: 6 to <24 months, 24 to <48 months, 48 to <72, and 72 to <96 months. Linear mixed models were used to analyze changes in raw BMI, BMI z-scores, energy expenditure, and ambulation function. Results: Pre- and post-surgical data were available for 363 children diagnosed with CP who underwent SDR (219 males, 144 females; mean age 6y [SD 2y 1mo]; mean BMI z-score 0.09 [SD 1.21]). Data from additional post-surgical time points were collected on subsamples. Although raw BMI significantly increased (p<0.01), these increases were consistent with anticipated growth. BMI z-scores did not significantly change over the 10-year study period. Interpretation: Concerns of unhealthy weight gain following SDR are not supported by this study. Further work examining possible risk factors for BMI increase following SDR, as well as examining disparities in existing criteria for patient selection, is merited.