This was a quasi-experimental study that examined two Project-Based Learning (PjBL) environments to determine the impact PjBL has on the changing perceptions of 21st century soft skills, and students' intrinsic motivation. Further, researchers were interested in evaluating the difference in results between an interdisciplinary PjBL experience and a non-interdisciplinary PjBL experience. The fundamental elements of PjBL are well suited to stimulate soft skill development and produce intrinsic motivation in participants. Researchers used a Non-Equivalent Group Design to collect and organize data. Students were asked to rank order 21st century skills in order of their perceived importance of which skills were most important for early career success. The "Partnership for 21st Century Skills" framework was used to describe the skills, as they have been used widely to illustrate the abilities needed for the challenging demands of the global workplace. In addition, students completed an Intrinsic Motivation Inventory (IMI) cultivated from research in Self-Determination Theory (SDT). A factor analysis was completed to determine the unidimensional nature of the Interest/Enjoyment sub-scale that measures intrinsic motivation and was found to be unidimensional in this study. Using several multivariate regressions and a multiple regression, researchers determined that PjBL may have an effect on the perceived level of importance for 21st century soft skills, such as Information Technology Application, and students' intrinsic motivation is improved when the project is interdisciplinary and tied to a students' area of interest. It can be inferred from this study that authentic projects that are of personal interest to a student population may develop appropriate perceptions of soft skills and have higher levels of intrinsic motivation. [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.]