Most things that children need to learn are developed and practiced in play. The purpose of the study was to examine how play influences learning development of preschool children in Ngong Ward, Kajiado North Sub-County. The objectives of the study were to find out the influence of availability of play materials, establish the influence of teachers’ perceptions on play and find out the influence of integrating play into teaching and learning on learning development of preschool children in Ngong Ward. The study employed the cognitive theory of play. The researcher adopted explanatory survey and correlational research designs to collect the data and answer research questions. The target population of this study was drawn from 79 pre-schools in Ngong Ward in Kajiado North Sub County. Twenty four schools were sampled to take part in this study. The respondents were the head teacher and a preschool teacher from each of the sampled schools. Data was gathered using structured questionnaires, observation schedules and interview schedules. Using test retest technique, teachers’ questionnaire was found to have a reliability coefficient of 0.82. Data were analyzed using both descriptive and inferential statistics. It was found that most of the preschools in Ngong ward had the most basic play materials. However, most teachers’ emphasized academic work and thus, the facilities were underutilized. The study found that independent variables contributed 72.6 % of variance in pupils’ learning development (R2 = 0.726). Integration of play into teaching and learning had the most significant relative influence to the prediction of pupils’ learning development (β = 0.526, p < 0.05) followed by the availability of play materials (β = 0.473, p < 0.05) while the teachers’ perception had the least and insignificant influence (β = 0.294, p = 0.142). The study recommends standardization of basic play material in preschools through ministry of education, and standardization on number of sessions teachers engage in learning on play during class activities.