This study aims to see how the influence of family communication on children's social competence in SD Arrahman Full Day School Medan. The type of research used is quantitative and data collection tools used in this study are family communication questionnaire and social competency questionnaire that uses 4 answer criteria namely very often (SS), often (S), sometimes (KD), and very rarely (JS). The subjects in this research were all students consisting of grades 1 to grade VI SD Arrahman Full Day School Medan, amounting to 159 people. Analysis of the data used in this study with the moment product correlation test and t test using SPSS 21 for Windows. The results showed that the significance value was less than (0.05) ie 0.044 <0.05 so it can be said that there is a correlation between family communication with social competence in children.