ABSTRACT The main of this study was to investigate the relationship of home environment and psychosocial development of preschool children in Mois-Bridge Zone, Uasin-Gishu County, Kenya. The study was guided by three specific objectives of the study: to examine the home environment (household factors and parental and family factors) of parents of preschool children, to determine the level of psychosocial development of preschool children and to establish the relationship between home environment and psychosocial development of preschool children in Uasin-Gishu County, Kenya. Quantitative method was used because it provided the fundamental connection between empirical observation and mathematical expression of quantitative relationships. Moreover, correlation design was preferred because of its ability to establish the relationship between variables i.e. independent variable (home environment) and dependent variable (psychosocial development). A total target at 378 respondents; the minimum sample size of 190 was obtained using Krejcie and Morgan (1970) table for determining sample size from a give population. To ensure validity of instruments, the instruments were developed under close guidance of the supervisor. After designing the questions, the researcher conducted a pre-tested. This helped to identify ambiguous questions in the instruments and contributed to re-align the questionnaires to the objectives. The questionnaires were given to the supervisor to judge the validity of questions basing on to the objectives. The researcher administered one type of questionnaire to all the participants. As well the researcher used Cronbach’s alpha. The composite reliability takes into account that indicators have different loadings and can be interpreted in the same way as Cronbach’s α (that is, no matter which particular reliability coefficient is used, an internal consistency reliability value above .70 is regarded as satisfactory, whereas a value below .60 indicates a lack of reliability). To achieve objective one, the researcher used both frequency and percentage and means and standard deviation. This is because some items under household and parental and family factors are categorical while others are numerical. Therefore, the researcher used this analysis tools to achieve this objective. To achieve objective two of the study, the researcher used means and standard deviation to find out the extent of child development. This is because the variable (psychosocial development) are Likert scaled and numerical in nature. Items of travelling distance from home to important facilities and media use, these are numerical and thus their relationship with psychosocial development was analysed using correlation and simple linear regression analysis. Finding showed that the null hypothesis was rejected this is because the r value was .287 and the sig. was .004 of which was less than 0.05. This implies that there were a relationship between home environment and psychosocial development of preschool children among primary school children in Uasin-Gishu County, Kenya. 70% of psychosocial development of preschool children in Mois-Bridge Zone in Uasin-Gishu County, Kenya was caused by household, parental and family factors such as house environment, family size, and types of house, parenting education, income; space and playing materials. The psychosocial development of children in Uasin-Gishu County, Kenya is high. The level of cognitive development, social development, and emotional development are all high among preschool children in Uasin-Gishu County, Kenya. As well, there were a relationship between home environment and psychosocial development of preschool children among primary school children in Uasin-Gishu County, Kenya. Seventy percent of psychosocial development of preschool children in Mois-Bridge Zone in Uasin-Gishu County, Kenya and this was caused by household, parental and family factors such as house environment, family size, types of house, parenting education, income; space and playing materials factors. It was recommended to improve on the accessibility to media to preschool children. According to social learning theory, children learn more by observing and imitating what they hear and see and fathers should get involved in the development of children. Thus, using media can be one way of teaching children especially videos and TV as well as newspapers.