American universities awarded roughly 760,000 master’s degrees during the 2014–15 academic year, yet we know little about the payoff associated with these degrees, especially by field of study. Using new data from three states, the authors show that field of study is closely related to post-graduation earnings from master’s degrees. Master’s graduates in fields such as philosophy, art, and early childhood education have the lowest median earnings—often less than graduates with bachelor’s or even associate degrees.