Background : Speech delay is one of developmental disorders with varying prevalence. Speech delay is affected by several factors. One of them is extrinsic factor. Extrinsic factor is factor from the outside of the children’s self or from the environment which is stimulus that heard by the children. Siblings stimulate the children to support the development of the children in the family. The number of the siblings may associated with speech delay in children. Objective : To prove relationship between the number of the siblings in the children aged 1 – 3 years. Method : This was an observasional analytic study with cross-sectional design. The research sample was children aged 1 – 3 years enrolledin daycare Tamantirto, Kasihan, Bantul, DIY. Subject was chosen by purposive sampling. Sampling was done by interview to parents/caregivers. Speech delay was measured by capute scales. Data was analyzed by Chi-Square/Fisher Test with significance level of p<0,05. Result : The result of this study, there is no significant relationship between the number of the siblings with speech delay in the children aged 1 – 3 years with significace value (p=0,412). There were 43 respondents included in this study. This study found 7 respondent (16,3%) suspected speech delay, there are 2 respondents (4,7%) who don’t have sibling and 1 sibling that live in 1 house and 5 respondents (11,6%) who have 2 or more siblings that live in 1 house. Conclusion : The number of siblings is not associated with speech delay in children