How do political apologies affect domestic and foreign public opinion? Official apologies for past injustice have long been used by political leaders in diplomatic relations. Conventional accounts of apologies assume that they are beneficial for interstate relations, because they either signal peaceful intentions or convey respect for human rights. Yet these accounts often miss the extent to which apologies may have (adverse) domestic ramifications. We draw on an interdisciplinary scholarship across international relations, comparative politics, psychology, and sociology to explore how apologies affect both domestic and foreign public opinion. We test our theoretical intuitions using survey experiments fielded in the U.S. and Japan. Survey takers read about a situation in an American near the U.S. base in Okinawa commits a crime and the Japanese government demands an apology. We randomize information about (1) the hypothetical U.S. president’s gender and partisan affiliation, (2) the degree to which the U.S. apologizes and shows remorse, and (3) whether Japan invokes historical grievances about the use of atomic weapons during WWII. Our data collection thus far shows that citizens reward governments for making apologies. That effect is moderated by partisanship and ethnocentrism but surprisingly not beliefs about the utility of the US-Japanese alliance.