The main purpose of this research is to investigate language learning strategy use of Vietnamese and Thai university students using Oxford's Strategy Inventory for Language Learning (SILL). One main objective of the research was to compare different six aspects of language learning strategies (memory, cognitive, compensation, metacognitive, affective, and social) between Thai and Vietnamese students. The main research question was to learn about learning strategies Thai and Vietnamese university students used. The data of research were collected from 116 English major Thai university students and 174 English major Vietnamese students, using the SILL developed by Oxford (1990) as the instrument and interviews from 16 lecturers from Vietnam and Thailand. The findings revealed statistically significant differences in memory, cognitive, affective, and social strategies between Thai and Vietnamese students. The interview data were used to gain insight into the findings of the questionnaires. The findings of the research can be beneficial to teachers and educators who are involved in the education of both countries, providing better understanding of different aspects of language learning strategies used in learning English.