The purpose of this interpretive phenomenological qualitative study was to gain an understanding of student engagement and collaboration experiences of Millennial and Postmillennial students in the online higher education environment. Piaget's pedagogical constructivism theory, combined with the generational cohort theory of Mannheim, are cited as the authority, and served as the framework for this study. The problem that the study addressed was the lack of knowledge about Millennial and Postmillennial student engagement and collaboration in the online learning environment. As the online modality continues to grow, there has been corresponding research about the lived experiences of Millennial and Postmillennial students with engagement and collaboration in the online learning environment. The results of the study were from semi-structured interview data about the online learning experiences of 20 Millennial and Postmillennial participants at a public university. Thematic data analysis led to five major themes that revolved around (a) disconnected engagement, (b) underutilized resources for engagement, (c) student reliance on self-initiative, (d) improved options for collaboration, and (e) needs for supportive resources. This study addressed a persistent lack of knowledge about online learners amidst the growing diversity of the student body in e-learning environments. This research determined that as more Millennials and Postmillennial participate in online learning, higher education leaders must have access to first-hand information to provide holistic student experiences and improve the educational quality of an increasingly diverse multigenerational online learning environment. This study culminated in recommendations for potential improvements in online learning using multiple methods of inquiry such as interviews, focus groups, student representation on various platforms, and suggestions for future research to better meet the demands of online instructional delivery. [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.]