Research on guessing word meanings from context has been done since 1995 chiefly to explore the effect of unknown to known word ratios on successful guessing. This paper examines the correlation between successful guessing and the scores in term examinations and mock examinations. This study also examines differences according to grades, unknown word ratios, and types of contextual clues. The results showed that the correlation between successful, guessing and midterm and term examination scores was generally low regardless of grades, ratios, or types of contextual clues though there was one case where the correlation for all the participants was about 0.50 in each grade. The correlation between successful guessing and mock examination scores was generally higher than that between successful guessing and midterm and term examination scores though it was also the case generally for midterm and term examinations.