Teachers' classroom grading and assessment practices are important elements of assessment reform. The purpose of this study was to examine the effect of classroom learning factors such as class size, subject area, and school size on teachers' classroom assessment practices. The results of a survey of 513 high school teachers showed evidence that teachers had implemented some aspects of assessment reform and that one classroom learning factor (i.e., subject) had a modest effect on teachers' practices. The results also indicate a need for more research on factors that affect teachers' assessment decisions and the effect of these decisions on implementing assessment reform.