Empirical evidence shows that disadvantaged students tend to have less-qualified and less-effective teachers than their more-advantaged peers. These teacher quality gaps (TQGs), which have existed for decades and across many measures of student disadvantage and teacher quality, are an important factor explaining student achievement gaps between advantaged and disadvantaged students. Research by Dan Goldhaber, Vanessa Quince, and Roddy Theobald -- focusing on the sources of TQGs across different states and measures of teacher quality -- suggests that policy makers should consider both the setting and the type of gap they wish to prioritize when designing policies to address TQGs.