Two groups of Japanese students, 40 university students (aged 18-25) and 34 high school students (aged 13-15), assessed their own English language skills (listening, speaking, reading, and writing) after having lived in an English-speaking country for at least a year before returning to Japan. This evaluation was compared with objective listening test results and teachers' assessments of oral skills. Influence of such variables as age, sex, attitude toward English, English use patterns overseas, length of stay overseas, and time since return from overseas was also examined. Results show the college students felt their skills had deteriorated, and this was confirmed in listening and speaking tests results, particularly the longer the time since return. High school students' results show a correlation between self-assessment and language environment after return to Japan. Both groups found their classroom learning about English-speaking cultures most useful and their vocabulary study least useful. Issues in self-evaluation arising from the findings, particularly as they relate to age differences, and follow-up support after return from overseas are discussed. Contains 15 references. (MSE)