As part of a continuing series of research studies on stress in schools, this study examined the construct validity of peripheral temperature at the fingertips as a measure of school stress. Measurements were made in classes selected at random from 11 volunteer schools in South Carolina. Three types of correlational studies were undertaken: (1) peripheral temperature was residualized for extraneous variation associated with both ambient temperature and time of day, conceptualized as a point on the circadian thermal cycle; (2) the corrected peripheral temperature was tested in hypotheses on groups which were presumed to vary in average school stress; and (3) common variables used in describing schools were correlated with corrected peripheral temperature to identify those variables that were associated with school stress. A strong school effect was found in the variation in corrected peripheral temperature, and it was shown to increase as student experience in the school grew. Certain curricula, noted for their difficulty, were found to influence peripheral temperature in directions suggestive of increasing stress on the learner. While this research cannot assert the validity of corrected peripheral temperature as a measure of stress, it contributes some evidence in support of construct validity. Sixty tables and seven pages of references are provided; the appendixes consist of forms used in the study, including the field tested student attitude inventory. (NB)