BACKGROUND: Cerebral palsy is the most common physical disability in childhood. Mechanically assisted walking training can be provided with or without body weight support to enable children with cerebral palsy to perform repetitive practice of complex gait cycles. It is important to examine the effects of mechanically assisted walking training to identify evidence-based treatments to improve walking performance. OBJECTIVES: To assess the effects of mechanically assisted walking training compared to control for walking, participation, and quality of life in children with cerebral palsy 3 to 18 years of age. SEARCH METHODS: In January 2020, we searched CENTRAL, MEDLINE, Embase, six other databases, and two trials registers. We handsearched conference abstracts and checked reference lists of included studies. SELECTION CRITERIA: Randomized controlled trials (RCTs) or quasi-RCTs, including cross-over trials, comparing any type of mechanically assisted walking training (with or without body weight support) with no walking training or the same dose of overground walking training in children with cerebral palsy (classified as Gross Motor Function Classification System [GMFCS] Levels I to IV) 3 to 18 years of age. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. MAIN RESULTS: This review includes 17 studies with 451 participants (GMFCS Levels I to IV; mean age range 4 to 14 years) from outpatient settings. The duration of the intervention period (4 to 12 weeks) ranged widely, as did intensity of training in terms of both length (15 minutes to 40 minutes) and frequency (two to five times a week) of sessions. Six studies were funded by grants, three had no funding support, and eight did not report information on funding. Due to the nature of the intervention, all studies were at high risk of performance bias. Mechanically assisted walking training without body weight support versus no walking training Four studies (100 participants) assessed this comparison. Compared to no walking, mechanically assisted walking training without body weight support increased walking speed (mean difference [MD] 0.05 meter per second [m/s] [change scores], 95% confidence interval [CI] 0.03 to 0.07; 1 study, 10 participants; moderate-quality evidence) as measured by the Biodex Gait Trainer 2™ (Biodex, Shirley, NY, USA) and improved gross motor function (standardized MD [SMD] 1.30 [postintervention scores], 95% CI 0.49 to 2.11; 2 studies, 60 participants; low-quality evidence) postintervention. One study (30 participants) reported no adverse events (low-quality evidence). No study measured participation or quality of life. Mechanically assisted walking training without body weight support versus the same dose of overground walking training Two studies (55 participants) assessed this comparison. Compared to the same dose of overground walking, mechanically assisted walking training without body weight support increased walking speed (MD 0.25 m/s [change or postintervention scores], 95% CI 0.13 to 0.37; 2 studies, 55 participants; moderate-quality evidence) as assessed by the 6-minute walk test or Vicon gait analysis. It also improved gross motor function (MD 11.90% [change scores], 95% CI 2.98 to 20.82; 1 study, 35 participants; moderate-quality evidence) as assessed by the Gross Motor Function Measure (GMFM) and participation (MD 8.20 [change scores], 95% CI 5.69 to 10.71; 1 study, 35 participants; moderate-quality evidence) as assessed by the Pediatric Evaluation of Disability Inventory (scored from 0 to 59), compared to the same dose of overground walking training. No study measured adverse events or quality of life. Mechanically assisted walking training with body weight support versus no walking training Eight studies (210 participants) assessed this comparison. Compared to no walking training, mechanically assisted walking training with body weight support increased walking speed (MD 0.07 m/s [change and postintervention scores], 95% CI 0.06 to 0.08; 7 studies, 161 participants; moderate-quality evidence) as assessed by the 10-meter or 8-meter walk test. There were no differences between groups in gross motor function (MD 1.09% [change and postintervention scores], 95% CI -0.57 to 2.75; 3 studies, 58 participants; low-quality evidence) as assessed by the GMFM; participation (SMD 0.33 [change scores], 95% CI -0.27 to 0.93; 2 studies, 44 participants; low-quality evidence); and quality of life (MD 9.50% [change scores], 95% CI -4.03 to 23.03; 1 study, 26 participants; low-quality evidence) as assessed by the Pediatric Quality of Life Cerebral Palsy Module (scored 0 [bad] to 100 [good]). Three studies (56 participants) reported no adverse events (low-quality evidence). Mechanically assisted walking training with body weight support versus the same dose of overground walking training Three studies (86 participants) assessed this comparison. There were no differences between groups in walking speed (MD -0.02 m/s [change and postintervention scores], 95% CI -0.08 to 0.04; 3 studies, 78 participants; low-quality evidence) as assessed by the 10-meter or 5-minute walk test; gross motor function (MD -0.73% [postintervention scores], 95% CI -14.38 to 12.92; 2 studies, 52 participants; low-quality evidence) as assessed by the GMFM; and participation (MD -4.74 [change scores], 95% CI -11.89 to 2.41; 1 study, 26 participants; moderate-quality evidence) as assessed by the School Function Assessment (scored from 19 to 76). No study measured adverse events or quality of life. AUTHORS' CONCLUSIONS: Compared with no walking, mechanically assisted walking training probably results in small increases in walking speed (with or without body weight support) and may improve gross motor function (with body weight support). Compared with the same dose of overground walking, mechanically assisted walking training with body weight support may result in little to no difference in walking speed and gross motor function, although two studies found that mechanically assisted walking training without body weight support is probably more effective than the same dose of overground walking training for walking speed and gross motor function. Not many studies reported adverse events, although those that did appeared to show no differences between groups. The results are largely not clinically significant, sample sizes are small, and risk of bias and intensity of intervention vary across studies, making it hard to draw robust conclusions. Mechanically assisted walking training is a means to undertake high-intensity, repetitive, task-specific training and may be useful for children with poor concentration.