This study aims to examine the relationship between school maturity levels and speech and language development of children receiving preschool education. The correlational survey models was used to determine these relationships. The sample of the study consists of 44 boys and 58 girls who are studying in public schools in Meram district of Konya province in the 2022-2023 academic year and a total of 102 kindergarten students and 6 kindergarten teachers responsible for the education of these students. In the study, the Metropolitan School Maturity Test was used to determine the school maturity levels of the students as a data collection tool, and the Speech and Language Development Questionnaire was used to determine the students' speech and language development characteristics. The research data were analyzed by using SPSS 25 program. Accordingly, it was found that there was a significant positive relationship between the speech and language development of the students and the general preparation and number preparation sub-dimensions of school maturity. It was found that there was a significant differentiation in favor of girls between speech and language development by gender and all sub-dimensions of school maturity. It was found that there was no significant differentiation between the speech and language development levels of the students according to age; and in all sub-dimensions of school maturity, there was a significant differentiation in favor of the 6-year-old students according to age.