This study addressed the perceptions of Texas middle school principals about the middle school concept in Texas middle schools and the effect of selected variables on the implementation of the concept. In addition the study sought to determine whether Texas middle school principals' perceptions of implementation were comparable to the perceptions of national middle school principals and if relationships existed between Texas principals' perceptions and school district size. A questionnaire was developed to survey Texas middle school principals' perceptions concerning the desirability, the implementation of the concept of the middle school, and the effects which four variables had on concept implementation: (1) return to the semester plan, (2) Texas Assessment of Basic Skills requirement, (3) back-to-basics movement, and (4) lack of middle school certification. School districts were categorized according to size for surveying purposes. Data were computer processed to calculate frequencies, percentages, means, t test, and one-way analysis of variance.