Abstract The main purpose of this study was to investigate factors affecting socio-emotional development of preschool children in Bahir Dar City. The specific objectives were to identify the extent of teachers’ demographic factors affecting socio-emotional development of children, determine the extent of predictor variables to predict socioemotional development of children after controlling demographic variables, find out the statically significant relationship of factors with children’s socio-emotional development and explain teacher- child interactions with indoor and outdoor environment. In order to achieve intended objectives, mixed research approach sequential explanatory design was employed. Ten preschools were selected by stratified sampling technique with 120 participants. Questionnaire was developed from related literature. The questionnaire consisted of 38 closed–ended items and three observational guiding questions to enrich and triangulate the data. A descriptive statistics, Pearson correlation, independent sample t-test, ANOVA and linear hierarchical regression analysis methods were employed. Then data were analyzed by using SPSS version 21 and qualitative thematic analysis technique. The results showed that preschooler teachers’ socio-demographic characteristics were highly contributed for a shared variance than other predictors such as teachers’ attitude, empathy, classroom weather conditions and availability of play materials. Teachers who were married had a positive effect on children’s socioemotional development as compared to single teachers. Teachers who had a bachelor of degree educational status showed a significant mean difference than a certificate and diploma level. Teaching experience was significantly correlated in a positive way with children’s socio-emotional development, although teachers’ age was negatively correlated. The qualitative study also revealed that a conducive playground and teacherchild relationship had a great role for children’s socio-emotional development. In conclusion, the study revealed that preschool children’s socio-emotional development can be extremely predicted by the teachers’ demographic factors than other factors. Finally, the researcher recommended for preschool administrator should be employed degree graduate in ECCE and fulfill types of play materials, and teachers should be enhance their relationship with their children to improve children’s socio-emotional development. Keywords: attitude, children, socio-emotional development, play materials and preschool.