Developing autonomy-supporting instructional communication styles is essential for modeling skills, inspiring teacher-student interactions, and motivating students to personalize the learning experience in postsecondary career and technical education programs. The study, guided by self-determination theory's dialectical framework, examined if and to what extent teacher verbal and nonverbal immediacy behaviors and student motivation relate to student agentic engagement. Data were collected from students enrolled in associate's degree-bearing programs at a technical college located in Pennsylvania. The nonexperimental quantitative study applied descriptive and hierarchical regression processes to analyze the data and test the hypotheses. The descriptive analysis found slightly above-average scores for all variables in the study. Hierarchical regression analyses revealed a positive, significant variance between student overall motivation and student agentic engagement, and positive, but not significant, variances between teacher immediacy behaviors and student agentic engagement. These findings suggest an interactive relationship between immediacy behaviors as teacher motivating styles, student motivation, and student agentic engagement relative to the dialectical framework's sequence of events. A practical application of the findings is to adopt individualized faculty training on the utility of immediacy behaviors as autonomy-supporting motivating styles in the highly interactive postsecondary career and technical education environment. Developing teacher-student relationships through positive teacher immediacy behaviors could influence student motivation and agentic engagement to improve achievement and retention rates. Study limitations, implications for theory, and recommendations for future research were discussed. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]