Face-to-face, hybrid, blended, and online learning have all provided adult students flexibility in how they participate. However, these courses are constructed in a manner where the instructor dictates the mode of instruction. Student choice and flexibility are important for adult students. The purpose of this qualitative case study was to understand the experiences of adult learners in a HyFlex (flexible) learning environment. HyFlex learning provides students with choice on how they attend class through face-to-face, synchronous, and asynchronous technology. The theoretical framework for this study was andragogy, adult learning theory. Eight students taking three HyFlex graduate courses were interviewed for this study. The research questions from this study are (1) How do adult graduate students participating in a HyFlex course describe the benefits and drawbacks of a HyFlex model? (2) How do adult students engage in a HyFlex learning course? (3) How do adult graduate students self-direct and involve themselves in their learning in a HyFlex course environment? (4) How does the course design help or hinder adult graduate students in a HyFlex course? The research from this study found that participants found the flexibility of the format to be the main benefit of HyFlex. They also preferred HyFlex courses in comparison to online or hybrid course formats. The main drawback of HyFlex was difficulty in communicating with students that were not physically present. Most students preferred coming to class. This preference is informed by their negative experiences when taking an online course. Recommendations for practice include the suggestion that institutions should offer flexible learning opportunities that also offer face-to-face interactions. HyFlex courses should also be developed entirely as an online course and with classroom community in mind. [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.]