Academic lectures are potential sources of vocabulary learning for second language learners studying at universities where English is the medium of instruction, as well as those in English for Academic Purposes (EAP) programs. Topic-related vocabulary is likely to occur frequently in academic texts, and academic speech consists of a reasonable proportion of frequently occurring sequences of words. Yet no intervention studies have explored the potential for learning single words and collocations through viewing a video of an unmodified academic lecture. To address this gap, this study collected data from 55 EAP learners in China, following a pretest-posttest design. The experimental group (n = 28) watched a video of an academic lecture in which 50 target single words and 19 target collocations were presented while the control group (n = 27) received no treatment. Results show that viewing the lecture led to significant learning gains of single words at the meaning recall level and collocations at the form recognition level. Frequency of occurrence in the lecture appeared to significantly contribute to the learning of single words but not the learning of collocations. Prior knowledge of general vocabulary appeared to make no significant contribution to the learning of single words and collocations.