This study reports the findings of a research that was conducted on ten (10) Arab students, who were enrolled in a master of English applied linguistics program at Universiti Putra Malaysia. The research aimed at instrumentally analyzing the English stops produced by Arab learners, in terms of voice onset time (VOT); identifying the effect of their mother tongue on producing the English stops; and the extent Arabic speakers of English differentiate in terms of pronunciation between minimal pairs. The findings of the study showed that some of the subjects' VOT values were similar to native speakers of English. It was also found that the subjects could differentiate in terms of aspiration or voicing between /p/ and /b/, which refutes the assumption that Arab learners have a problem in producing the /p/ sound with appropriate aspiration. However, they did not show significant difference in pronunciation between the/t/and/d/or between the /k/ and /g/. Moreover, there is a kind of limited effect of the L1 on producing some stops (e.g./t/and /g/). However, for the /b/ sound, it cannot be inferred that there is interference from the mother tongue because its VOT value is almost the same in English and Arabic. This research suggests that teachers need to enhance Arab learners' pronunciation of some minimal pairs such as /t/ and /d/or /k/ and /g/.