The purpose of this study was to investigate nationwide enrollment in high school music courses from 1982 until 2009 to determine what trends in music enrollment existed and whether these trends were affected by the passage and implementation of the No Child Left Behind Act of 2001 (NCLB). With data from 10 separate nationally representative high school transcript studies conducted by the National Center for Education Statistics, a unique data set was constructed that tracked the transcript-indicated 9th- through 12th-grade music course enrollment patterns for the U.S. graduating classes of 1982, 1987, 1990, 1992, 1994, 1998, 2000, 2004, 2005, and 2009. Descriptive results showed that overall music enrollment patterns were relatively stable in the public schools, with roughly 34% of all students consistently enrolling in at least one music course during high school across all cohorts. Abbreviated interrupted time series analyses suggest that NCLB had no effect on overall music enrollment rates but exacerbated the preexisting underrepresentation in music courses of Hispanic students, English language learners, and students with Individualized Education Plans.