Background: Most United States schools include school-based physical fitness testing (SB-PFT), yet little evidence shows how it is implemented, perceived, and used. Purpose: 1) Explore stakeholders' experiences with SB-PFT; 2) identify: challenges in analyzing fitness data, ways schools can use fitness data, and predictors of meeting fitness benchmarks. Methods: Data were collected in a partner school district (King County, Washington, USA). We conducted and analyzed qualitative interviews with middle schoolers (n = 30), parents (n = 20), and school staff (n = 5); and identified student-level predictors of meeting fitness benchmarks with two-level mixed effects logistic regression models using district's fitness assessment data (grades 4-8). Results: Stakeholders identified challenges and provided feedback on SB-PFT, and predictors of meeting fitness benchmarks were identified. Discussion: Findings suggest SB-PFT has potential to be useful in promoting adolescents' fitness, but opportunities exist to improve the testing process and the ways that results are shared and utilized. Translation to Health Education Practice: Teachers would benefit from resources to understand and discuss the role of SB-PFT in a physically active lifestyle with students, ensure a positive testing experience by conducting assessments more privately and taking the time to practice assessments beforehand, and track testing outcomes and relevant demographics. A AJHE Self-Study quiz is online for this article via the SHAPE America Online Institute (SAOI) http:// portal.shapeamerica.org/trn-Webinars