Teachers in American schools have substantial autonomy in grading students in their courses. Music teachers have historically used a plethora of grading criteria that include non-academic and non-achievement data such as participation, attendance, and behavior. This study aims to show how music teachers in the state of Missouri are calculating students' final grades in ensemble courses: band, choir, and orchestra. The research further investigates the perceptions of standards-based grading held by ensemble teachers and provides insight into best practices for using standards-based grading by teachers who have implemented this grading process. Data for this project was collected using a Google form survey that was disseminated to Missouri music teachers through the Missouri Music Educators Association email list and Facebook group. The research focused on gathering information about current grading practices of Missouri music ensemble teachers and gathering perceptual data on the views of standards-based grading. This qualitative descriptive study used a survey, focus group and individual interviews to gather data on grading practices, perceptions of standards-based grading, and best practices of implementing standards-based grading in music ensemble courses. Participant data uncovered a high portion of respondents using non-academic and non-achievement criteria in grading students in secondary band, choir, and orchestra courses. Responses showed a lack of education in grading practices in undergraduate coursework and professional development opportunities. Perceptual data showed that teachers believe standards-based grading to be inefficient and incompatible with a music ensemble curriculum. [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.]