Many school change efforts aim to foster conditions for the development of students' twenty-first century skills in an equitable and comprehensive way, but methods to measure the frequency and quality of opportunities that students receive in school are lacking. In this study, we describe the design, testing, and initial evaluation of a self-report measure of high-school students' opportunity to learn and apply a core set of intrapersonal and interpersonal twenty-first century skills--collaboration, communication, creativity, critical thinking, and self-directed learning. Our sample included 9th graders (n = 522) from one large comprehensive high school in central California. Confirmatory factor analysis and multivariate regression modeling suggest promising reliability and validity to evaluate opportunities in high school learning environments. Based on this early evidence, the Student MetaSkills Survey appears to provide a way for school leaders and educators to evaluate the frequency and quality of key twenty-first century skills and take responsibility for providing equitable opportunities for students. Measuring inputs and processes, such as students' opportunity-to-learn, can play an important role in the process of educational improvement.