Performance assessments encompass a wide variety of activities, all of which require students to show what they know, rather than selecting answers from predetermined options on a multiple-choice test. For the graduate capstone, Oakland Unified School District (Oakland Unified) seniors conduct original research, write a paper based on the findings, and reflect upon their learning process. Students then present their research and analysis to a panel of judges and an audience of peers and community members. Oakland Unified built its graduate capstone work on an existing, though loosely defined, district graduation requirement called the senior project. The graduate capstone approach is grounded in research on how performance assessments can reliably assess student learning and also help students and educators strive for meaningful learning goals. The Oakland Unified case study draws on data from a range of sources, including documents, district administrative data, interviews with a range of personnel at the district and school levels, focus groups with teachers and students, observations of student performance assessments, and observations of professional learning opportunities for teachers. The study provides an in-depth description of how Oakland Unified has worked to advance districtwide implementation of the graduate capstone. The authors identified five emerging implications of Oakland Unified's performance assessment practices for student learning and teacher practice: (1) Districts can establish a strong and shared vision for why performance assessments matter; (2) Teachers and schools need supports to implement the vision; (3) Gradually cultivating buy-in can generate strong support for this work among early adopters; (4) Districts can allow sufficient flexibility for schools to make the work their own; and (5) Participating in performance assessments can shift teacher practice when effective supports are in place. This report is part of a series of three case studies examining the key district-, school-, and classroom-level conditions necessary to support high-quality performance assessment practices. All three districts (Los Angeles [ED610904], Oakland, and Pasadena [ED610902]) actively participate in the California Performance Assessment Collaborative (CPAC), a community of educators, researchers, and technical assistance providers who are working to study and advance the use of performance assessments throughout the state. A cross-case study that accompanies this report provides insights across all three case study districts, as well as recommendations for district policymakers interested in implementing well-designed performance assessments within their own context. [For the cross-case study, see ED610900.]