The purpose of this quantitative study was to understand the placement of ninth-grade students within advanced mathematics courses. High school counselors are often criticized for being an ineffective resource in the placement of students of color and low-income students into such classes; even though their professional mandates state that they advocate ensuring educational equity, access, and academic success for all students (Beale, 2003). Mathematics is important for students who want to enter the Science, Technology, Engineering, and Mathematics (STEM) workforce. Enrollment of U.S. students majoring in STEM fields and pursuing STEM careers are the basis for the surveys in the High School Longitudinal Study of 2009 (HSLS:09). For the U.S to compete in a global economy that is increasingly technologically based, a skilled STEM workforce is an essential (National Academies, 2010). This study was based upon the secondary analysis of data collected by the National Center for Education Statistics (NCES) High School Longitudinal Study of 2009 (HSLS:09). HSLS:09 is composed of a stratified random sample of 21,444 ninth graders in 944 schools that was representative of the 50 United States and the District of Columbia at that time (Ingels et al., 2011). Mathematics placement decisions in the ninth grade can determine a student's overall math trajectory in high school. The importance of taking rigorous high school mathematical courses is critical to the preparation for STEM careers, whether a student applies for college or goes directly to the workforce. Thus, it becomes important to examine the enrollment process for high school mathematics courses. Responses to the school counselor survey were used to examine factors in the placement of typical ninth-grade students into mathematics courses. Descriptive statistics, exploratory data analysis, factor analysis, and ordered logistic regression were used to analyze data from the High School Longitudinal Study of 2009 (HSLS:09), in order to more closely examine the issue of student placement into high school mathematics courses. Findings revealed that most counselors in the study believed middle school achievement and middle school courses to be the most important factors in determining a student's course placement in ninth-grade mathematics. Notably, a student's career/education plan was found to be of little importance for ninth-grade mathematics course placement, though a few counselors in the study did indicate that it was an important factor. From the counselors' responses, three themes emerged as significant factors for ninth-grade mathematics course placement: students' past performance, students' performance on tests, and students' future potential. Each of the factors examined in the current study fell under one of these themes. Students' past performance included middle school achievement, middle school courses, and middle school teacher recommendations; students' performance on tests included standardized tests as well as placement tests; and students' future potential included student/parent choice and the student's career/education plan. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]