The efficiency of partial body weight-supported treadmill training (PBWSTT) for treating various conditions in children and adolescents with cerebral palsy (CP) in diverse contexts of rehabilitation, households, or schools is unknown. The major objective of this systematic review and meta-analysis was to analyze the effectiveness of PBWSTT on various outcomes in different contexts among children and adolescents with CP. We incorporated full-text, randomized controlled trial studies that specifically assessed the effects of PBWSTT walking, motor function, stride, balance, and endurance in children and adolescents aged 3 to 18 years with CP. The literature search was carried out using Google Scholar, PubMed, Web of Science, CINAHL Plus, Scopus, PEDro, and ResearchGate databases. The methodological quality was evaluated using a Cochrane risk of bias instrument. A meta-analysis of pooled data from 10 studies with 255 participants demonstrated that PBWSTT for 4–12 weeks in rehabilitation (mean difference [MD] = 1.94, 95% confidence interval [CI] = 1.40—2.48, p < 0.0001), at home or in a school context (MD = 13.5, 95% CI = 13.9—16.0, p < 0.0001), was significantly effective for treating various conditions in children and adolescents suffering with CP. The period of 4–12 weeks of PBWSTT in rehabilitation and at-home/school settings is effective on various outcomes in children or adolescents with CP.