This investigation, which was conducted on the post-secondary level and included vocational and academic students, was undertaken to develop an instrument to assess the attitude and knowledge of students concerning body language and to develop a module of instruction in body language to favorably influence their attitude and knowledge concerning body language. Hypotheses were formulated related to the differences in mean effective and cognitive scores of the experimental group who were taught body language and the control group. Additional hypotheses were formulated related to mean differences in the scores of students differing in age, sex, business experience, and prior exposure to body language. The findings of this study included first, the testing of the instrument; second, the testing of the validity of the research design and third, the testing of the hypotheses. The following conclusions are based on the findings of the study: the instrument seems to be acceptable for assessing the attitude and knowledge of post—secondary students concerning body language, the module of instruction in body language seems to be acceptable as a basis for influencing the attitude and knowledge of post—secondary students concerning body language, the mid-management and speech students were comparable in attitude and knowledge concerning body …