On the assumption that a teacher's credibility with his students is related to student learning, a measure of teacher credibility was developed and tested. Data obtained from 1,80 students in basic speech communication courses from two universities indicated five dimensions of teacher credibility: “Character,” “Sociability,” “Composure,” “Extroversion,” and “Competence.” These dimensions were found useful for predicting some aspects of student learning. A 14‐item instrument for the measurement of teacher credibility is recommended.