The aim of the present study was to investigate the role of temperament and emotion regulation on social behaviors at 4 to 6 years of age. 238 (114 male and 124 female) children's mothers and classroom teacher participated in the cross-sectional study. Children's temperamental characteristics were measured by using The Short Temperament Scale for Children-Parent Form (STSC), emotion regulation skills were assessed by using Emotion Regulation Checklist-Parent and Teacher Forms (ERC) and Social Behavior Scale (PSBS-T) was used. The results showed that 4-year-olds were significantly less prosocial than 5 and 6 year olds. No effect of gender has been found on social behaviors. The relationships between emotion regulation skills and prosocial behavior and aggression were significant. It was seen that reactive children were less skilled in emotion regulation and prosocial behavior. It was also found that highly reactive children who also had less emotion regulation skills exhibited more physically aggressive behavior.