Japan’s fisheries, among the largest in the world, are currently facing overcapacity. As of 2017, approximately half of the 37 stocks with abundance estimates were either overfished or subject to overfishing. In response, in December 2018, the government of Japan enacted revisions to the Fisheries Act which was modeled partly on the systems used in the United States and the EU. Implementing these changes will take time, as lessons learned from other countries are incorporated. Over the past 26 years, the United States has undergone a similar succession of amendments to its fisheries law, yielding a system that has been largely successful in reducing overfishing and rebuilding overfished fisheries. We compare the Japanese and U.S. approaches to fisheries management in four areas that may explain the differences in the number of stocks that are overfished: 1) overall structure of fisheries management and who is responsible for conducting the management, 2) the specificity and goals of fisheries laws in each country, 3) the role and independence of science in the management process, and 4) the approach to scientific and management uncertainty.