Language learning is of great importance for university students, especially those studying English as a Second Language (ESL) programs, as it fosters the development of academic vocabulary. However, researchers in Malaysia have not given sufficient attention to this aspect of foreign language education in universities. To address this gap, we conducted a pilot study with 31 BTESL students from UKM to validate a questionnaire exploring factors influencing the development of academic vocabulary knowledge among ESL undergraduates. The study comprised five sections (A, B, C, D, and E) assessing demographic data, students' perceptions of academic vocabulary relevance, familiarity with academic word lists, vocabulary learning strategies, and vocabulary competence, respectively. The questionnaire exhibited high reliability (Cronbach's alpha of 0.94) across all items, indicating its suitability for future research. The pilot study offers valuable insights into the academic vocabulary development of ESL students at UKM.