Background: Childhood cancer outcomes in low-and middle-income countries (LMICs) lag behind those in high-income countries (HICs), in part due to late presentation and diagnosis. Though several interventions targeting early detection of childhood cancer have been implemented in LMICs, little is known about their efficacy. Methods: We conducted a systematic review to identify studies describing such interventions. We searched multiple databases from inception to December 4, 2019. Studies were included if they reported on LMIC interventions focused on: (a) training of health care providers on early recognition of childhood cancer, or (ii) public awareness campaigns. We used preferred reporting items for systematic reviews and metaanalyses (PRISMA) guidelines to conduct our review. The risk of bias in nonrandomized studies of interventions (ROBINS-I) checklist was used to assess quality of studies. Results: Twelve studies met inclusion criteria (n = 5 full text, n = 7 abstract only). Five studies focused on retinoblastoma only, while the others focused on all types of childhood cancer. The majority studied multiple interventions of which early detection was one component, but reported overall outcomes. All identified studies used pre-post evaluative designs to measure efficacy. Five studies reported statistically significant results postintervention: decrease in extraocular spread of retinoblastoma, decrease in rates of refusal/abandonment of treatment, increase in number of new referrals, increase in knowledge, and an absolute increase in median 5-year survival. Other studies reported improvements without tests of statistical significance. Two studies reported no difference in survival postintervention. The ROBINS-I checklist indicated that all studies were at serious risk of bias. Conclusion: Though current evidence suggests that LMIC interventions targeting early detection of childhood cancer through health professional training and/or public awareness campaigns may be effective, this evidence is limited and of poor quality. Robust trials or quasi-experimental designs with long-term follow up are needed to identify the most effective interventions. Such studies will facilitate and inform the widespread uptake of early detection interventions across LMIC settings.