This  qualitative  study  explores  the  distinctive  aspects  of  teaching  English  for  Specific Purposes  (ESP)  to  military  forces, through  the  lens  of  a  Vietnamese  EFL  teacher’s experiences.  The  research  focuses  on  understanding  the  unique  challenges  and  strategies involved in military ESP teaching, set within the context of a public institution in the Mekong Delta  region  of  Vietnam. Employing  semi-structured  interviews, the  study  delves  into  the teacher’s reflections, revealing key themes such as the importance of adapting to the specific linguistic needs and operational contexts of the military, the integration of military culture and  hierarchy  into  language  learning,  and  the  emphasis  on  discipline  and  structured approaches.  The  analysis  is  informed  by  two  theoretical  frameworks:  the  concept  of  ESP teaching and the Zone of Proximal Development (ZPD), offering insights into the tailored content  and  pedagogical  adjustments  required  in  military  settings.  Findings  highlight  the necessity for ESP programs to be meticulously customized for military contexts, emphasizing practical  application  and  cultural  sensitivity.  The  study  underscores  the  need  for  ESP educators  to  have  a  deep  understanding  of  military  hierarchy  and  culture,  and  for  teacher training programs to include components on contextual sensitivity. The findings contribute to the field by outlining specific pedagogical strategies and content considerations essential for effective ESP teaching in military contexts.