Aim: To examine long-term outcomes of selective dorsal rhizotomy (SDR) 10 to 17 years after surgery. Method: Participants who underwent SDR had spastic diplegic cerebral palsy (CP), completed baseline gait analysis, and were 16 to 25 years old at follow-up. Non-SDR participants (i.e. controls) were matched on important clinical parameters at baseline but did not undergo SDR. All study participants completed six surveys assessing pain, quality of life, participation, function, and mobility. Treatment history for lower extremity surgery and antispasticity injections was tabulated. A subset of each study group returned for three-dimensional gait analysis, including kinematics, metabolic energy cost, and physical examination. Gait Deviation Index (GDI) was calculated to measure gait quality. Results: The study cohort had 24 participants with SDR and 11 without SDR. Of these, 13 patients with SDR (five males, eight females; median [IQR] age 17y 2mo [16y 8mo–17y 9mo]) and eight without SDR (three males, five females; median [IQR] age 19y 2mo [17y 3mo–21y 11mo]) completed baseline and follow-up gait analysis. Spasticity significantly decreased in those with SDR (p<0.05). Gait Deviation Index improved more in participants without SDR than those with SDR (Δnon-SDR=12.8 vs ΔSDR=9.1; p=0.01). Compared with the SDR group, participants without SDR underwent significantly more subsequent interventions (p<0.05). Interpretation: Patients in both the SDR and non-SDR groups showed improved gait quality more than 10 years after surgery. Participants without SDR had a larger improvement in gait pathology but underwent significantly more intervention. There were no differences between groups in survey measures. These results suggest differing treatment courses provide similar outcomes into early adulthood. What this paper adds: Selective dorsal rhizotomy (SDR) and non-SDR groups had significant improvement in gait pathology over time. The non-SDR group had significantly better gait compared with the SDR group at follow-up. The groups had similar levels of energy cost, pain, and quality of life. Non-SDR participants underwent significantly more orthopaedic surgery and antispasticity injections than SDR participants. Use of a clinically similar control group highlights that different treatment courses may result in similar outcomes into young adulthood.