The aim of this research was to examine the relationship between contextual factors and the academic achievement of fourth-grade students, utilizing a mixed-methods approach with Iranian TIMSS 2019 data. The research was applied in nature, and methodologically, it followed a descriptive survey design. The statistical population included all Iranian fourth-grade students, both boys and girls, who participated in the TIMSS 2019 assessment. The sample consisted of 224 schools and a total of 6,010 fourth-grade students (boys and girls), with an average age of 10.2 years, who took part in the TIMSS 2019 study. To collect the necessary data regarding students' academic achievement in mathematics and science, TIMSS 2019 employed the student achievement test booklets and associated questionnaires related to five domains: curriculum, school, teacher, student, and parents. This included five test booklets for mathematics and science and five background questionnaires. The data analysis was conducted using correlation methods and multilevel regression, utilizing R software and the lmeR package. Reliability was assessed through Cronbach’s alpha coefficient. The results showed that the student-level, parent-level, teacher-level, school-level, and curriculum-level variables had a significant relationship with mathematics achievement, and these relationships varied at the school (class) level (P ≤ 0.01). Similarly, the student-level, parent-level, teacher-level, school-level, and curriculum-level variables had a significant relationship with science achievement, and these relationships also varied at the school (class) level (P ≤ 0.01).