The purpose of this study is to measure the impact of Korean speakers’ English stop pronunciation on their general pronunciation proficiency. For these purposes, 20 Korean speakers read English sentences and their pronunciations were rated by native English speakers. The Korean speakers’ VOT values of English stops in sentences were then measured and the relation between the VOT values and native speakers’ pronunciation rating was compared. Here, the relation between (1) the proficiency score of each speaker and VOT values; and (2) the proficiency score of each sentence and VOT values were analyzed. The results show that there is a relation between the proficiency score of each sentence and VOT values of /t, b, d, g/; and there is a relation between VOT values of /t, b, d, g/ and proficiency scores of each speaker while these is a weak relation between VOT values of /p, k/ and proficiency scores of each speaker.