This monograph reports the development of a semantic differential designed to measure professional self perception in student teachers. Seven scales were identified by factor analysis of the responses of 396 student teachers to 56 adjectival pairs used to rate the concepts "Myself,""Myself as I would like to be,""Myself as a teacher," and "The teacher I would like to be." The seven scales measure self perception along the dimensions of creativity, orderliness, warmth-supportiveness, satisfaction, clarity, energy-enthusiasm and non-conformity. Selection of items for the scales involved consideration of possible concept-scale and subject-scale interactions. Reliability estimates are reported. Construct validity is examined from the viewpoint of predicted systematic differences in self perception between male and female student teachers, and primary and secondary student teachers. Examples of the uses of the scales in evaluative research in teacher education are described. Two instruments, the Original Semantic Differential and the Professional Self Perception Questionnaire, are included as appendices. (Author/RL)