Using the United States data from the 2019 Trends in International Mathematics and Science Study, which included a total of 9924 randomly selected students in grade eight from 325 randomly selected schools, the present study examined the relationship between the students' attitudes toward mathematics and the mathematics achievement of the students. Due to the hierarchical structure of the educational data, multilevel statistical modeling was used to analyze the data. While including sex and parent education level as student-level control variables and school location and school socioeconomic status as school-level control variables, the students' attitudes toward mathematics demonstrated significant positive effects on the students' mathematics achievement. Furthermore, this relationship was shown to vary significantly across schools; however, school disciplinary climate was not found to be a significant contributor to this variation.