Toilet training is an important developmental milestone for toddlers, because the ability to control the urge to urinate and defecate begins to develop at this time. At present, many mothers work outside the home, so there is less time to stimulate children's toilet training. The purpose of this study was to determine the relationship between mother's support and toilet training success in toddlers aged 18-36 months at Posyandu Jemunang Pandanrejo Wagir Malang. The design of this research is correlation analytic with the cross sectional approach. The research sample is 30 respondents with a total sampling technique. The research instrument was a questionnaire filled out by mothers who had toddlers aged 18-36 months. The results showed that most of the mother's support was in the category of good support (66.67%). The success of toilet training is partly in the success category (53.33%). The results of data analysis using Spearman rank (rho) obtained 0.614, significant value (p-value) = 0.000 with α 0.05. Conclusion: there is a significant relationship between maternal support and toilet training success in toddlers aged 18-36 months. Parents, especially mothers, are expected to continue to provide support to children when doing toilet training.