This study aims to examine the effects of some demographic variables on the social-emotional development, academic grit and subjective well-being of fourth-grade primary school students. The sample of this cross-sectional study consisted of 582 fourth grade primary school students. Data were collected using the Social-Emotional and Character Development Scale, the Academic Grit Scale, and the Subjective Well-Being in School Scale. It lasted around 30 min to answer the data collection tools. Data were analyzed using the SPSS 23 program. In this study, the levels of social-emotional development, academic grit and subjective well-being were higher in female students who received preschool education, and had a high frequency of daily book-reading. In addition, the multivariate main effects of students' gender, preschool education and frequency of daily book-reading were significant. Relevant trainings can be organized in cooperation with universities and school counselling services to raise awareness of both teachers and families about daily book-reading. This can have an impact on students' academic grit, subjective well-being and social-emotional development.