Working adult students may have difficulty mastering complex concepts when taking courses online. Researchers have argued there is a need for in-person, peer-teacher interaction available in traditional classrooms that is lacking online. The purpose of this dual-focus phenomenological study was to explore the meaning of purposeful interpersonal interaction and the experience of content mastery among undergraduate working students taking online psychology courses. Constructivism and adult learning theory guided the study. Semi-structured interviews were conducted with 10 working adults with experience taking online psychology courses within the last 2 years. Data were analyzed using Moustakas's guidelines. Results indicated that participants experienced interpersonal interaction and content mastery of complex course concepts when provided with clear course design and expectations, instructor-peer interactions, and detailed instructions. Findings may lead to positive social change by informing and improving the learning experience for working adults taking online courses. [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://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]