Whether there were differences in motivational and learning environment perceptions of students selected based on their performance on the Texas Assessment of Academic Skills (TAAS) was studied over 3 years in a public school district in Texas. The degree to which affective elements of student behavior varied according to their success on this state criterion-referenced tests was investigated with approximately 30 high scoring, 30 middle scoring, and 30 low scoring students in grades 5, 8, and 11. Students completed the Multidimensional Motivation Instrument (MMI) and the Instructional Learning Environment Questionnaire (ILEQ). Differences were found in perceptions of motivation across and within grade levels. Differences were also found in the variance of students' perceptions of motivation according to their performance on the TAAS. Results provided evidence that student motivation is a potential mediating factor for performance. The findings have practical implications that would encourage teachers to be more sensitive to the affective needs of students. The trend in this district for low-performing students to decline in all of the affective dimensions is a problem. (Contains 3 tables and 17 references.) (SLD)