Zinc has a significant benefit in saving children's lives. It decreases severity, diarrhoeal duration, and death rates. However, evidence on zinc utilisation, trends, and predictors among under-five children with diarrhoea in Ethiopia was sparse and inconclusive. This study aimed to assess the pooled zinc utilisation, trends, and predictors among under-five children with diarrhoea in Ethiopia. This study used Ethiopian demographic and health survey (EDHS-2005-2016) data with a total weighted sample size of 29,525 among under-five children with diarrhea. A multilevel mixed-effects logistic regression analysis was used to identify predictors of zinc utilisation. An adjusted odds ratio (AOR) along with a 95% confidence interval (CI) was used to estimate the strength of the association. The pooled zinc utilisation among under-five children in Ethiopia was 8.96% (95% CI: 7.44, 10.76%). In Ethiopia, the proportion of zinc utilisation by under-five children decreased from 0.22% (95% CI: 0.07, 0.74%) in EDHS 2005 to 0.04% (95% CI: 0.00, 0.22%) in EDHS 2011, and sharply increased to 33.60% in EDHS 2016. After adjusting for other background characteristics, having mothers complete primary education [AOR = 3.16, 95% CI: 1.57, 6.35] was a significant predictor of zinc utilisation among under-five children with diarrhea. The findings revealed that zinc utilisation was considerably low among Ethiopian under-five children with diarrhoea compared to reports from low-income countries. Ethiopia should pursue strategies to boost zinc utilisation in this group of population.