Child development at the age of 1–5 years is a critical period that determines the quality of growth and development in later life. One of the factors that plays an important role in supporting child development is maternal knowledge regarding growth and development. This study aimed to determine the relationship between the level of maternal knowledge about growth and development and the development of children aged 1–5 years in the working area of Susut II Public Health Center.This study employed a quantitative design with a cross-sectional approach involving mothers who had children aged 1–5 years in the working area of Susut II Public Health Center. The sample consisted of 92 respondents selected using a purposive sampling technique. The instruments used were a maternal knowledge questionnaire on growth and development and a child development assessment sheet using the Pre-Screening Development Questionnaire (KPSP). Data were analyzed using univariate and bivariate analysis with the Spearman correlation test.The results showed that most mothers had a good level of knowledge regarding child growth and development, and most children were categorized as having appropriate development. The Spearman correlation test obtained a significance value (p-value) of 0.000 (p < 0.05) with a correlation coefficient (rho) of 0.562, indicating a significant relationship with moderate strength between maternal knowledge of growth and development and the development of children aged 1–5 years.This study concludes that there is a significant relationship between maternal knowledge of growth and development and child development among children aged 1–5 years at Susut II Public Health Center. Therefore, mothers are expected to improve their knowledge of child growth and development through posyandu activities and health information sources to support optimal child development.

Keywords: Children Aged 1-5 Years, KPSP, Mother's Knowledge, Child Development, Growth and Development.