Online higher education courses are often designed using a one-size-fits-all model that treats students as instructional users rather than participants who contribute according to their learning needs and interests. Although many scholars have discussed personalized learning as a means to customize instruction over the past three decades, few have investigated the impact of personalized learning interventions. In particular, there is a gap in the literature on interventions using customized instructional content in online courses to provide individuals with opportunities to address their own learning needs and choices. The purpose of this study was to investigate the effect of this instructional approach on students' self-determination, intrinsic motivation, learning engagement, and online learning experiences. The researcher applied a convergent parallel mixed-methods design to collect, analyze, and merge quantitative and qualitative data simultaneously. Qualitative findings have converged with and diverged from the quantitative data. Quantitative results revealed that personalized learning has a statistically significant effect on students' perceived feelings of autonomy and their online learning experiences. The approach also showed a significant effect on students' perceptions toward their instructors. The findings showed that the majority of learners perceived personalized learning to be an effective instructional approach. According to the qualitative findings, this approach showed a positive effect on students' self-determination (autonomy and competence), intrinsic motivation, engagement, and online learning experiences. However, the intervention did not show a positive effect on students' feelings of relatedness. This study may contribute to the understanding of effective and influential teaching and learning approaches, especially in online learning environments. The final findings might inform educators, instructional designers, and instructors about the personalized learning potential of tailoring online courses to students' needs and interests, which may increase student motivation and engagement. [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.]