The present study investigates how foreign language learners of Japanese (JFL learners) in the US respond in misunderstanding situations, and whether interpersonal relationship and situational factors affect their behaviors. Twenty-nine JFL learners who are native speaker of American English are presented with a series of misunderstanding situations and are asked to tell the likelihood of them saying something about the problems and write what they may say if they are to respond. The results show that the learners tend to respond verbally, in both serious and trivial misunderstanding situations. Also, they tend to defend their position and try to find the cause. In addition, they make explicit statements, instead of using mitigating expressions. Although the learners are more confrontational and willing to resolve the conflict than native speakers of Japanese, they are also sensitive to social hierarchy and degree of intimacy in that they tend to apologize more often to social superiors and acquaintances than to social equals and friends.