The success of language learning significantly depends on multiple sets of complex factors; among these are language-learning strategies of which learners in different countries may show different preferences. Needed areas of language learning strategy research include, among others, the strategy of grammar learning and the context-based approach to learning strategies. To fill in these gaps, this study aimed at finding the grammar learning strategies adopted by high school students as well as exploring the national differences between Chinese and Thai students. The results showed that in general the strategies significantly taken up by the high achievers in the grammar test included the metacognitive, the memory, the social and the cognitive. In terms of the national differences, the strategies that characterized the Thai students were the social and the affective. Regarding the Chinese, even though they generally applied all strategy categories at lower frequencies, they were found to prefer different sub-strategies in the following three categories: memory (revision and space reliance), cognitive (note taking) and metacognitive (lesson preview). The findings lead to implications for learners of grammar, interesting future research in grammar strategies and culturally responsive grammar teaching.