The purpose of this study was to determine the level of agreement or disagreement between principals and teachers when using established criteria to measure the effectiveness of a science teacher. To obtain this information, 28 principals and 81 science teachers were randomly selected to complete an instrument for their perceptions of an outstanding science teacher. The respondents involved in this study were employed in the English-speaking high schools in the Province of Québec, Canada. The questionaire was constructed from a model based on the theoretical framework of previous research in science education and instructional theories. The data collected from the two populations were tested using the arithmetic mean, Pearson chi-square and cross tabulation using the Lambda & Gamma tests to determine the strength or form of the association between the two variables (position and perception). Results indicated that the high school principals and science teachers agree on the relative importance for most of the evaluative criteria. From such results it was possible to construct a profile of the attributes of an outstanding science teacher, and also, to make recommendations to school board officials, school principals, science teachers, and researchers in the field of education.