Objective: To assess the effectiveness of group wheelchair maintenance training and investigate participant characteristics associated with responsiveness to training. Design: Randomized controlled trial with an immediate group and a waitlist control group (WLCG) who received the intervention after a 6-month delay. Setting: Four Spinal Cord Injury Model Systems Centers. Participants: Manual (MWC; n=80) and power wheelchair (PWC; n=67) users with spinal cord injury (N=147). Interventions: Two 90-minute structured wheelchair maintenance training program classes with 12-20 people per class and separate classes for MWC and PWC users. Each class included in-person hands-on demonstrations and practice of wheelchair maintenance. Main Outcome Measures: Separate analysis was completed for MWC and PWC users using the Wheelchair Maintenance Training Questionnaire (WMT-Q) capacity (ability to complete), performance (frequency of completion) and knowledge at baseline, 1 month, 6 months, 6 months pretraining (WLCG only), and 1 year (immediate only). Results: After the intervention, participants in both the immediate and WLCG improved in maintenance capacity (MWC and PWC, P<.001) and performance (MWC and PWC, P<.001) with training. Only PWC users improved knowledge of wheelchair maintenance (P<.001). For both WLCGs (MWC and PWC), there was no difference between the 6-month pretraining time point and baseline. MWC users who responded to training had lower WMT-Q scores for all domains, whereas this was only the case for knowledge for PWC users. Conclusions: Group wheelchair skills training is effective at improving capacity to complete maintenance and performance of maintenance activities for MWC and PWC users, even in a cohort of experienced wheelchair users. For MWC users, improvements were tied to lower WMT-Q scores at baseline, whereas PWC users improved in capacity and performance independent of baseline score. Delivering this training in a structured group format has a lower cost, which might improve adoption into clinical practice.