The United States Physics Olympiad (USAPhO) is a national physics competition program organized by the American Association of Physics Teachers (AAPT) to identify and challenge the most talented high school physics students in the U.S. It is part of the selection process for the American team that competes at the International Physics Olympiad (IPhO). Students typically begin by taking the **F=ma** exam, an introductory mechanics-focused multiple-choice test. High scorers on F=ma are invited to sit for the more advanced **USAPhO** exam, which features challenging, multi-step written problems covering a broad range of high school and introductory college-level physics topics. Top USAPhO performers are invited to a training camp, where a final team is selected to represent the United States at the IPhO. Participation offers deep problem-solving experience, exposure to advanced physics, and a strong credential for STEM-focused college applications. USAPhO is open to high school students in the United States (citizens or permanent residents, with additional rules for students in U.S. schools abroad). Schools or coaches generally register students through AAPT, and many participants prepare via physics classes, self-study, or school-based physics clubs.