The purpose of this study was to explore the utility of the theory of planned behavior for predicting the behavioral intentions of teachers enrolled in the Institute in Physical Science, an EESA, Title II program funded by the Texas Higher Education Coordinating Board. In particular, the study investigated three determinants of teachers' behavioral intentions (BI) set forth in the theory of planned behavior, namely, attitude toward the behavior (AB), subjective norm (SN), and perceived behavioral control (PBC). The behavior of interest in this study was the intention of teachers in grades 5/6 or 9/10 who were enrolled in the Institute to use 50% of the activities and investigations completed in the program with students they would teach during the next school year. Data were collected from 50 elementary and secondary teachers. Simple and hierarchical regression analyses were used to determine the relative contributions of attitude, subjective norm, and perceived behavioral control (and their interactions) to the prediction of behavioral intention. Results of this study indicated that attitude, subjective norm, and perceived behavioral control made significant contributions to the prediction of behavioral intention. Examination of the data blocked on external variables revealed attitude toward the behavior to be the single most important predictor of behavioral intention. Intent to perform the behavior appears to be totally under the control of most teachers, with little need for social support and with ample resources and sufficient opportunities available to perform the behavior.