Abstract Background Family-based interventions are important in promoting adolescent sexual health outcomes. However, the effectiveness of these interventions in promoting adolescent sexual and reproductive health (ASRH) in Lower and middle-income countries (LMIC) has not been empirically evaluated. This review aimed to summarise the effectiveness of family-based sexual and reproductive health interventions in promoting ASRH in LMIC. Methods We conducted a systematic search for studies published in English from 2000 to October 2023 using MEDLINE, PsyINFO, CINAHL, Web of Science, and EMBASE databases. Studies were included if they involved adolescents aged 10-19 years, included family members in a key intervention component, evaluated the effectiveness of the interventions using an experimental or quasi-experimental design, assessed ASRH outcomes reported by adolescents and were conducted in LMIC setting. Standardized mean difference (SMD) and 95% confidence intervals were computed and meta-analyses were conducted using random effect models. Results Ten articles involving 2,246 participants were included in the review. The studies were nostly conducted in Africa. Across studies, there was no significant impact of family-based interventions in improving adolescent sexual health knowledge (SMD=0.5, 95%CI: -1.98 to 2.98), attitudes (SMD= -0.05, 95%CI: -1.92 to 1.82), practices (SMD=0.53, 95%CI: -0.69 to 1.75), or sexual communication with their family (SMD= 0.14, 95%CI: -0.42 to 0.7). Although individual studies reported a mixed effect of family-based interventions in improving sexual health outcomes, the pooled results from the meta-analysis showed no significant impact of family-based interventions. Conclusions Our review did not find any significant impact of family-based interventions in improving ASRH in LMIC. We recommend interventions using innovative approaches and novel strategies to align with the socio-cultural and economic background of the study setting. Key messages • This study found no significant impact of family-based interventions in improving ASRH in LMIC. • Additional studies, particularly from Asia, using culturally relevant interventions is required in this area.