The aim of this study is to determine the school readiness level of primary school students and to examine whether the school readiness levels differ according to various variables. Descriptive screening model was used in the study. The universe of the research is composed of primary school first grade students who study in Istanbul province. The sample of the research is composed of 976 primary school first grade students who study first class in Bagcilar, Küçükçekmece, Esenyurt, Esenler and Gaziosmanpasa districts in Istanbul province. The "Primary School Readiness Scale" was used as the data collection tool in the study. As a result of the data analysis, it was seen that the level of readiness to school of primary school first grade students is high according to the average of general total and affective skills, psychomotor skills, self-care skills and cognitive skills subdimensions. The level of school readiness of the primary school first grade students is significantly different according to gender, the pre-school education status, age as of September and education level of mother and father. There is a significant difference of the level of readiness to school of primary school first grade students in favor of girls according to gender variable; in favor of who have preschool education according to the pre-school education status, in affective skills, psychomotor skills, self-care skills and cognitive skills sub-dimensions and general total. In the subdimensions of affective skills, psychomotor skills, self-care skills, and cognitive skills, the students who were 72 months of age or older in as of September as a whole had higher level of readiness to school, followed by students between 66-71 months and 60-65 months. In the subdimensions of affective skills, psychomotor skills, self-care skills, and cognitive skills, the students whose mother and father graduated from university have higher levels of readiness to school, followed by high school graduates, junior high school graduates and primary school graduates respectively.