The present study was designed to investigate the effect on performance of the relationship between teacher expectancy and self-expectancy. For the induced expectancy, a random half of 96 high school students enrolled in a four-week summer language course of a Christian association were described to the instructors as having high success potential. The remaining trainees served as controls. Correct scores on the learning task, instructor ratings of behavior and attitude of the instructors were measured on three sessions of the course. Ratings of teacher's behavior were factor-analyzed and four interpretable factors emerged: Support, Caring, Attention, and Tutoring. The induced expectancy and specific levels of self-expectancy had significant effects on the subjects' performance and ratings of the instructor. It was concluded that self-expectancy mediates the effects of teacher expectancy on learning performance. Implications of these results for the Pygmalion effect were discussed.