The purpose of this dissertation work is to investigate sustainability incorporations in undergraduate mechanical engineering curricula. Engineering decisions have deep impacts on people and the planet. Therefore, it is important for all engineers to learn engineering that integrates these important factors. This work starts with an evaluation of 100 mechanical engineering undergraduate programs for sustainability inclusions in their courses. There were 82 institutions found to include sustainability in either an elective or required undergraduate mechanical engineering course, 41 institutions were found to include sustainability in at least one required course, and 15 institutions were found to have 10 or more courses integrating sustainability. Courses with the greatest frequency of sustainability inclusion are thermodynamics, engineering design, introduction to engineering, heat transfer, fluid mechanics and mechanics of materials. Subsequently, systematic literature reviews were completed for scholarship of teaching and learning articles on sustainability in engineering design and thermodynamics courses. For Thermodynamics courses, the described teaching methods include mathematical examples, labs, projects, service learning, application-based learning, use of simulation-based tools and book reviews. In design courses the most found pedagogies for incorporating sustainability were active learning, project-based learning, hands-on/building, and lectures. Within these design courses, 72% included environmental considerations and 28% included all three pillars (social, economic, and environmental). Of the 17 United Nations Sustainable Development Goals, numbers 7 (affordable and clean energy) and 12 (responsible consumption and production) were included in approximately 50% of the design courses studied, followed by goals 8 (decent work and economic growth) and 11 (sustainable cities and communities) which were each included in 22% of the design courses. Lastly, questionnaires, a discussion group, and interviews with leaders in sustainability education in mechanical engineering were completed and synthesized with Diffusion of Innovations theory. Peer to peer support and meeting the needs of faculty surfaced as primary factors in the diffusion of sustainability integration in mechanical engineering courses. Suggestions for meeting the needs of professors in wanting to include sustainability in their curriculum are supportive policy, incentives, training, prepared curriculum, mentorship programs, bandwidth, consistency, and meeting student needs. Peer-to-peer connections and networks can both meet faculty needs and support faculty in a variety of facets. The results of this work should help catalyze mechanical engineering programs to incorporate sustainability more widely throughout the undergraduate curriculum. This will in turn grow the sustainability awareness and abilities in mechanical engineering graduates and help to amplify the consideration of sustainability in engineering decisions. [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.]