Imagine a school with no principal and with a leadership structure that holds teachers accountable for the learning of all students. About 50 such teacher-led schools currently operate across the United States, and this article tells the story of one of them. The Mathematics and Science Leadership Academy (MSLA) in Denver, Colorado, serves about 300 students in grades K-5. Ninety-five percent of the students qualify for free or reduced-price lunch, and 70 percent are English language learners. Lori Nazareno, a teacher at the school, points out that teachers today are often held accountable for things over which they have no control. MLSA attracts the most highly skilled teachers by giving them authority and autonomy to make authentic decisions on behalf of students. Nazareno describes how the school's teacher teams, peer observation and evaluation, and emphasis on service learning and passion areas have helped spread ownership of learning throughout the school staff. She also describes the challenges that teacher-led face--especially those like MLSA, which has chosen to operate within the district rather than as a charter school.