Action research was undertaken to better understand teachers' perceptions of grading at a single P-12 school district in a midwestern state. The motivation for measuring teachers' perceptions of grading came from the school district's local data, which suggested a possible disconnect between students' grades and what students know, understand, and are able to do. Specifically, data found a disparity between students' report card grades and performance on standardized achievement assessments. The researcher hypothesized that teachers would perceive that grades serve many different and often contradictory purposes, which may affect the reliability, validity, and fairness of grades. The Teachers' Perception of Grading Practices scale was used to record teachers' perceptions of grading. The results of the quantitative, cross-sectional survey study concluded that the hypothesis should be accepted. Teachers reported using grades to communicate achievement and acknowledge student effort. Teachers in some subject areas reported using grades for classroom management. Ultimately, there was consensus among participants about many aspects of grading. Some of these beliefs, like the use of non-academic factors in grading, and teachers' relative autonomy in determining grading practices, may unintentionally threaten the reliability, validity, and fairness of grades. Differences in some perceptions recorded may also have the same effect. Elementary teachers signaled that they would be more likely to pass a student with a failing grade if the student showed effort. Secondary teachers' responses did not mirror that sentiment. Perceptions also varied by teacher subject area on the role of homework, class participation, and behavior in grading. [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.]