This study examines the development of interactional competence (Hall, 1993, 1995) by English-speaking learners of Japanese as a foreign language (JFL) in a study abroad setting, as indexed by their use of the interactionally significant particle "ne." The analysis is based on a comparison of (a) 6 sets of conversations between JFL learners and native Japanese peers during the first week of the study abroad program, and (b) 6 sets of conversations between the same pairs of speakers during the fifth week of the program. Although there is great variability in efficiency of interactional competence acquisition among JFL cohorts, JFL learners on the whole seem to have enhanced their interactional competence by using more "ne" alignments. This study supports the argument that a study abroad program provides a valuable developmental experience that can accelerate JFL learners' acquisition of interactional competence.