The mother's ability to stimulate children greatly determines the success of the stimulation of the first thousand days of life to support children's intelligence. The low ability of the mother to stimulate causes the child to get less stimulation so that he is vulnerable to experiencing deviations in child development and even permanent disorders. This study aimed to determine the effect of telenursing on the mother's ability to stimulate the development of children aged 9-12 months. This study used a pre-experimental research design with a pretest posttest one group design approach. Sampling used purposive sampling technique. The sample of this research was 16 people. This research instrument used SOP and SAP to assess telenursing and the SDIDTK checklist to assess the mother's ability to stimulate development based on the SDIDTK book. Data analysis used Wilcoxon test. The results suggested that there was an increase in the mother's ability to stimulate development from medium, as many as 10 people (62.5%), to high, as many as 14 people (87.5%). The Wilcoxon test results obtained a p-value of 0.000 or