Time use in different activities in junior high school is described, and relationships between class time use and student achievement, behavior and attitude are examined. A total of 102 English and mathematics classes were observed for about 9 hours each. Data included descriptive narratives, time logs, student engagement ratings and observer ratings of student and teacher behavior. Results showed that there is much variation in the way individual junior high school teachers use class time, within a limited number of activity structures. Significant relationships were found between time use and class achievement and attitude in mathematics classes, but not in English classes. (Author/BW)