Construction project teams expend substantial effort to develop scope definition during the front end planning phase of building projects but oftentimes neglect to sufficiently plan for the complexities of tribal building projects. A needs assessment conducted by the author comprising interviews with practitioners familiar with construction on tribal lands revealed the need for a front end planning (FEP) process to assess scope definition of capital projects on tribal lands. This dissertation summarizes the motivations and efforts to develop a front end planning tool for tribal building projects, the Project Definition Rating Index (PDRI) for Tribal Building Projects. The author convened a research team to review, analyze, and adapt an existing building-projects-focused FEP tool, the PDRI – Building Projects, and other resources to develop a set of 67 specific elements relevant to the planning of tribal building projects. The author supported the facilitation of seven workshops in which 20 industry professionals evaluated the element descriptions and provided element prioritization data that was statistically analyzed to develop a preliminary weighted score sheet that corresponds to the element descriptions. Given that the author was only able to collect complete data from 11 projects, definitively determining element weights was not possible. Therefore, the author leveraged a Delphi study to test the PDRI – Tribal Building Projects. Delphi study results indicate the PDRI – Tribal Building Projects element descriptions fully address the scope of tribal building projects, and 75 percent of panelists agreed they would use this tool on their next tribal project. The author also explored the PDRI – Tribal Building Projects tool through the lens of the Diné (Navajo) Philosophy of Sa’ąh Naagháí Bik’eh Hózhóón (SNBH) and the guiding principles of Nistáhákees (thinking), Nahat’á (planning), Iiná (living), and Sihasin (assurance/reflection). The results of the author’s research provides several contributions to the American Indian Studies, front end planning, and tribal building projects bodies of knowledge: 1) defining unique features of tribal projects, 2) explicitly documenting the synergies between Western and Diné ways of planning, and 3) creating a tool to assist in planning capital projects on tribal lands in the American Southwest in support of improved cost performance.