Interventions to reduce household air pollution (HAP) are key to reducing associated morbidity and mortality in low-and middle-income countries (LMICs); especially among pregnant women and young children. This systematic review aims to determine the effectiveness of interventions aimed to reduce HAP exposure associated with domestic solid biomass fuel combustion, compared to usual cooking practices, for improving health outcomes in pregnant women and children under five in LMIC settings. A systematic review and meta-analysis was undertaken with searches undertaken in MEDLINE, EMBASE, CENTRAL, GIM, ClinicalTrials.gov, and Greenfile in August 2020. Inclusion criteria were experimental, non-experimental, or quasi-experimental studies investigating the impact of interventions to reduce HAP exposure and improve associated health outcomes among pregnant women or children under 5 years. Study selection, data extraction, and quality assessment using the Effective Public Health Practice Project tool were undertaken independently by two reviewers. Seventeen out of 7293 retrieved articles (seven pregnancy, nine child health outcome; 13 studies) met the inclusion criteria. These assessed improved cookstoves (ICS; n = 10 studies), ethanol stoves (n = 1 study), and Liquefied Petroleum Gas (LPG; n = 2 studies) stoves interventions. Meta-analysis showed no significant effect of ICS interventions compared to traditional cooking for risk of preterm birth (n = 2 studies), small for gestational age (n = 2 studies), and incidence of acute respiratory infections (n = 6 studies). Although an observed increase in mean birthweight was observed, this was not statistically significant (n = 4). However, ICS interventions reduced the incidence of childhood burns (n = 3; observations = 41 723; Rate Ratio: 0.66 [95% CI: 0.45-0.96]; I 2 : 46.7%) and risk of low birth weight (LBW; n = 4; observations = 3456; Odds Ratio:Identification Screening Eligibility Included Database sources MEDLINE -4306 EMBASE -4335 CENTRAL -27 WHO-ICTRP -45 GIM = 75 ClincialTrial.Gov-31 ClincialTrial.Gov -31 Greenfile -1547 Excluded -6987 No Access to abstract -3 Excluded Articles -286 Incorrect population ‡-43 Wrong study design -90 Not biomass fuels or intervention -71 Incorrect health outcomes -54 Not LMIC setting -4 Reviews -15 Protocols -6 Ongoing studies -3 Alternative sources † Hanna et al 2016 Wylie 2017 Total results -10367 Full paper review -302 13 studies included for narrative syntheses -reported in 16 articles Pregnancy outcome -6 Child health outcomes -9 Screened by title and abstract -7293 12 studies included for meta-analysis -reported in 15 articles Pregnancy outcomes -5 Child health outcomes -6 § Duplicates removed -3074