This study explored the production of 11 English vowels by Acehnese Indonesian EFL students. Ten undergraduates (five males and five females) from the Pidie District, Aceh, participated, with Acehnese and Bahasa Indonesia as their first languages, and English learned formally at school since the 7th grade. Using PRAAT, recordings of vowel elicitations were measured and analyzed, revealing distinctions in vowel pairs. Statistical tests were employed to compare vowel productions between the males and females. The results showed that the females produced many of the vowel pairs similarly: /i:/-/[near-close near-front unrounded vowel]/, /[open-mid front unrounded vowel]/-/[near-open front unrounded vowel]/, /u:/-/[near-close back rounded vowel]/, /[open-mid back unrounded vowel]/-/[open back unrounded vowel]?/, and /[open back unrounded vowel]?/-/[open back rounded vowel]/. The pairs they differentiated were /[open-mid central unrounded vowel]:/-/[open-mid back unrounded vowel]/ and /[open-mid back rounded vowel]:/-/[open back rounded vowel]/. However, the female students could not discriminate between the long and short vowel pairs. Meanwhile, the male students could distinguish the following pairs: /i:/-/[near-close near-front unrounded vowel]/, /[open-mid central unrounded vowel]:/-/[open-mid back unrounded vowel]/, /[open-mid back unrounded vowel]/-/[open back unrounded vowel]?/, and /[open-mid back rounded vowel]:/-/[open back rounded vowel]/. The others, /[open-mid front unrounded vowel]/-/[near-open front unrounded vowel]/, /u:/-/[near-close back rounded vowel],/ and /[open back unrounded vowel]?/-/[open back rounded vowel]/, were produced similarly. Additionally, they could distinguish the long and short vowels in the /[open-mid central unrounded vowel]:/-/[open-mid back unrounded vowel]/, /u:/-/[near-close back rounded vowel]/, /[open-mid back unrounded vowel]/-/[open back unrounded vowel]?/, and /[open back unrounded vowel]?/-/[open back rounded vowel]/ pairs, but not /i:/-/[near-close near-front unrounded vowel]/, /[open-mid front unrounded vowel]/-/[near-open front unrounded vowel]/ and /[open-mid back rounded vowel]:/-/[open back rounded vowel]/. This study has shown complex distinctions in the production of English vowels by Acehnese Indonesian EFL students. These findings underscore the importance of considering gender-specific phonetic patterns in English language acquisition, providing valuable insights for language educators and researchers.