The purpose of this study was to examine the relationships between principals' leader behavior and teacher morale in the private secondary schools of Bangkok, Thailand. This study also determined whether significant relationships based upon the factors of age, sex, educational level, years of teaching experience, salary, and size of school existed between the morale of teachers and their perceptions of the principals' leader behavior. The sample of the study was comprised of 400 teachers in private"secondary schools in Bangkok, Thailand. Each teacher was asked to complete the Purdue Teacher Opinionaire (PTO), an instrument designed an instrument designed to identify a principal's leader behavior which consists of two dimensions: initiating structure and consideration. Of the 400 returned questionnaires, 399 were usable. The statistical treatments applied to the data thus obtained included the Pearson product moment, Multiple regression, and Canonical correlation. A .05 level of significance was the criterion for accepting or rejecting each hypothesis.