The purpose of this study was to ascertain whether elementary school principals were as knowledgeable about reading instruction as classroom teachers; whether classroom teachers viewed their principals as a main source of assistance in reading instruction; and whether professional courses, experience, preference for teaching reading, and membership in the International Reading Association (IRA) were associated with knowledge of reading instruction. Subjects were given the Inventory of Teacher Knowledge of Reading. Information sheets designed by the researcher and completed by the subjects provided other data. The findings indicated that: (1) elementary school principals possessed knowledge about reading instruction equal to that of classroom teachers; (2) classroom teachers did not perceive their principals as best sources of help in matters of reading instruction; (3) professional experience of one or two years did not necessarily mean more knowledge about reading instruction; (4) members of IRA did not possess greater knowledge about reading instruction than did teachers who were not members; and (5) subjects who had taken two or more professional courses in the teaching of reading were more knowledgeable about teaching reading than those who had not. (Author/WR)