Instructors often lament on students’ limited critical reading skills due to “vocabulary deficit.” Therefore, this study investigated the vocabulary size and vocabulary learning strategies of 120 ESL respondents in a tertiary institution in Malaysia. Data were collected using a vocabulary test, a questionnaire, and semi-structured interviews. The findings revealed that the most favoured strategies were “determination strategies” which reflected respondents’ usage of shallow thinking while least favoured were “cognitive strategies” that demanded higher-level mental processing. No significant difference was recorded in strategy use based on gender. No relationship was found between the respondents’ vocabulary size and vocabulary learning strategies.