BACKGROUND: Child undernutrition has short and long term consequence for both individuals and society. Previous studies show probiotics may promote child growth and have an impact on under-nutrition. METHODS: A systematic review of the literature was carried out on three electronic databases to assess evidence. The outcome measured was change in weight or height. A narrative analysis was conducted due to heterogeneity of included studies. RESULTS: Twelve studies were included in the review of which ten were randomised controlled trials. A total of 2757 children were included, with 1598 from developing countries. The studies varied in type and quantity of probiotics given, duration of interventions, characteristics of participants, setting and units of outcome measures. Overall, five studies found a positive effect of probiotics on child growth. All five were conducted in developing countries with four studies conducted in mostly under-nourished children and one in well-nourished children. No significant effect on growth was found in the seven studies that were conducted in developed countries. CONCLUSION: The limited evidence suggests that probiotics have the potential to improve child growth in developing countries and in under-nourished children. More research is needed to explore this further.