This updated systematic review and meta-analysis examines the effectiveness of repeated low-level red light (RLRL) therapy in slowing the progression of myopia in children. Twenty randomized controlled trials (RCTs) with a total of 1053 participants were analyzed, of which 515 were in the RLRL group and 538 were in the control groups. Studies were searched in PubMed, Web of Science, Cochrane Library, Embase, CNKI, VIP and Wanfang databases from their inception to May 2023. Main findings show standardized mean difference (SMD) for reduction in spherical equivalent of refraction (SER) 0.84 (95% CI: 0.50, 1.19), for reduction in axial eye length (AL) -1.01 (95% CI: -1.60, -0.41) and for increased choriocapillary layer thickness (SFChT) 0.81 (95% CI: 0.65–0.98). No major publication bias was detected. Myopic children undergoing RLRL in addition to normal treatment showed significantly slower disease progression than the control group. The study is registered in PROSPERO under number CRD420251034037.