The purpose of this study was to delineate the development of the Computerized Evaluation Protocol of Interactions in Physical Education, a data collection program for multiple interaction behavior measures in elementary inclusive physical education settings. The theoretical and empirical base for the Computerized Evaluation Protocol of Interactions in Physical Education is described in a three-phase study presenting (1) development of 25 multi-component interaction behavior items from presented literature, (2) content related evidence of validity evaluated by international adapted physical education experts, and (3) strong evidence of convergent validity of the Computerized Evaluation Protocol of Interactions in Physical Education. Overall, the outcomes of multiple studies indicated that the Computerized Evaluation Protocol of Interactions in Physical Education demonstrates promise for the adapted physical education research and assessment by documenting interaction behaviors in elementary physical education environments. (Contains 3 figures and 4 tables.)