The problem of readjustment to the home culture among international students who have spent some time in a foreign culture has not received satisfactory empirical investigation in the literature. We present a longitudinal study of the readjustment of 199 Japanese adolescents who have been enrolled in 1-year placement with a host family in various countries of the world. The personality trait, coping style, social support, and emotional distress of the subjects were measured before departure, while abroad, and 6 months after return home. The students showed substantial emotional distress even 6 months after return from a foreign sojourn; neuroticism, emotion-oriented coping, and concurrently measured social support were found to significantly predict mental health during readjustment. Close attention is recommended not only for the adjustment of the international students while abroad but also for the readjustment process involved in the so-called reverse culture shock.