Innovation is a popular topic that receives significant attention from both organizations and academics. This attention includes scholars, executives, public entities, and private organizations in the construction and infrastructure fields. Scholars have examined innovation in both construction and public-private partnerships (P3s). Despite this work, gaps remain — particularly regarding the impact of project-level factors on technical innovation in P3s. Hence, this dissertation contributes to the areas of infrastructure innovation and P3s using a three pronged approach. First, exploration of the literature identified 348 factors that drive or inhibit innovation in infrastructure projects. These factors were synthesized into 33 aggregate factors such as client, integration, and risk. Subsequently, case interviews with practitioners revealed 110 factors that influence innovation in P3 projects; these were further grouped into six main categories. Literature and practitioner perspectives were strongly aligned around four predominant factors influencing innovation in P3 projects: i) risk, ii) client, iii) procurement, and iv) project type. Second, a framework to identify and classify project level innovation was derived and tested using deviations from project baselines submitted as alternative technical concepts (ATCs) in four infrastructure project procurements. The developed framework provides the infrastructure and construction community with a replicable approach to assess technical enhancements in projects to determine whether they are innovative or not and if so the type of innovation. Application of the framework classified only 7 of 53 ATCs from the four projects as innovative. However, the remainder added significant value through cost savings, improved safety or operational efficiency. Lastly, a case study of six contemporary US highway P3 projects: i) Elizabeth River Tunnels in Virginia; ii) East End Crossing in Indiana; iii) North Tarrant Expressway segments 3AandB in Texas; iv) I-4 Ultimate Improvement in Florida; v) I-77 HOT Lanes in North Carolina; and vi) SH 288 Toll Lanes in Texas was conducted to determine the types of innovation found and to assess the influence of key project characteristics on P3 technical innovation. Technical enhancements proposed by concessionaires were assessed using project documentation and semi-structured interviews with 23 experienced public and private sector project participants. Innovations were uncovered, albeit limited. Procurement, project type, and payment mechanism (demand risk/traffic risk) were the key project characteristics influencing innovation. Further, these same characteristics promoted added-value in the form of increased safety, reduced project durations, and decreased project costs. Together, the three studies advance our understanding of the effect of project attributes on technical innovation and value creation in infrastructure public-private arrangements.