This study describes and evaluates an experimental program for reducing tardiness in a rural junior high school. The subject school housed approximately 1,500 seventh- and eighth-grade students. Under the "Lock Out Program," first-time tardy students were given a one-day work detail in the cafeteria for 15 minutes of their lunch period. Two tardies resulted in a two-day work detail and the student's parents were informed. Three tardies required a parent conference before the student could return to school. For the fourth and each subsequent tardy, students could choose a day's suspension or an after-school work detail. School staff had voiced dissatisfaction with the school's previous tardy policy, saying it lacked consistency and was too time-consuming. A review of the literature showed that consistency of dealing with tardies was the most important factor. Under the new program, teachers kept statistics on tardiness, which were compared with pre-implementation data. Feedback was gathered from administrators and teachers. Results showed an 87% decrease in the number of tardies and a substantial decrease in the amount of time administrators spent disciplining tardy referrals. There was a 20% increase, however, in out-of-school suspensions during the implementation period. A survey showed that 25 teachers who previously had reported tardiness to be a problem no longer thought it was a problem after implementation of the lock out program. It is concluded that the program should be continued at the school and that it should be given wider implementation. Appendices provide tables and figures, plus information on survey instruments. (TES)