Knowledge of academic collocations is important for academic communication. Examining its relationship with knowledge of academic words and general high-frequency words should provide insights into the relative value of prior knowledge of different kinds of single words for the development of collocational knowledge in academic contexts, thus expanding our understanding of vocabulary knowledge beyond the current conception of individual word knowledge. Yet no studies have addressed this issue, mainly due to the lack of validated tests for academic words and collocations. This study employed three pairs of newly developed tests to measure Vietnamese EFL learners’ knowledge of academic collocations, academic words, and general high-frequency words. Results showed that at the form-recall level, both academic word and general high-frequency word knowledge were positively associated with academic collocation knowledge, with academic words having a stronger relationship. At the form-recognition level, only academic words and academic collocations were positively correlated.