Every Student Succeeds Act (ESSA) requires states to ensure the equitable distribution of out-of-field teachers. Using over 180 million student-course-teacher records from Texas between 2011-12 and 2017-18, we found out-of-field teaching rates have increased dramatically since ESSA became law. We also found vast inequities in which teachers are assigned to teach out-of-field and dramatic differences in student out-of-field course-taking rates across demographic characteristics. The strongest predictors of teachers teaching out-of-field is that they work in a charter school or completed alternative certification programs. Black teachers and students are most likely to teach and take courses out-of-field, and Latinx teachers and students are least likely. Policy implications are considered given negative impacts of out-of-field teaching on student academic achievement.