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Introduction Acute watery diarrhoea remains a leading cause of global paediatric morbidity and mortality. Low-osmolarity oral rehydration solution (ORS) is the current WHO-recommended treatment. Alternative formulations, including adding amino acids, substituting glucose for polymers and the addition of zinc, have been developed with the potential to reduce diarrhoea duration and severity. These have been compared to the old or current WHO standard, but their relative efficacy remains unclear. Therefore, this network meta-analysis was conducted to determine the most effective ORS for treating acute diarrhoea in children.Methods CENTRAL, MEDLINE, EMBASE, AMED, Global Health, EBM Reviews CINAHL, and LILACS were searched from inception to 14th November 2025 for randomised controlled trials comparing different ORS formulations in children with acute watery diarrhoea. Primary outcomes were diarrhoea duration (hours) and 24-hour stool-output (g/kg). Unscheduled IV fluids was a secondary outcome. A random effect frequentist network meta-analysis was performed using NMAstudios and MetaInsight. Evidence quality was assessed using the Confidence in Network Meta-Analysis (CINeMA) framework.Results 96 trials, including 18,023 participants from 37 countries were analysed. Low-osmolarity ORS was the standard comparator. Zinc-supplemented ORS had the shortest diarrhoea duration (MD -16.52 h, 95% CI -23.15 to -9.89; low certainty evidence) and ranked best (SUCRA 0.98). Standard-osmolarity ORS was the least effective for diarrhoea duration (SUCRA 0.07; MD 4.12 h, 95% CI 0.001 to 8.248; low certainty evidence) and resulted in greater 24-hour stool output (MD 17.56 g/kg, 95% CI 4.56 to 30.55; SUCRA 0.05; low certainty evidence). Polymer-based and amino acid-glucose ORS showed no significant benefit over low-osmolarity ORS in the network (low and moderate certainty). Pairwise comparisons indicated that both zinc-ORS and polymer-ORS significantly reduced stool output compared to low-osmolarity ORS (MD -15.67 g/kg, 95% CI -22.50 to -8.84; and MD -4.42 g/kg, 95% CI -7.68 to -1.15, respectively). There was no difference for unscheduled IV rehydration requirement between ORS types. Confidence in the evidence was mainly downgraded due to incoherence and heterogeneity, partially explained in sub-group analysis by dehydration status, varying income level of countries and poor methodological quality of studies.Conclusions Zinc-supplemented ORS appears the most effective for reducing diarrhoea duration, and standard-osmolarity ORS is the least effective for both variables, supporting current WHO guidelines. Quality of evidence was poor overall, and further multi-centre trials directly comparing polymer-based and amino acid formulations with zinc supplementation are needed to draw more confident conclusions.