This study investigated the effectiveness, as well as EFL learners’ perceptions, of the keyword method (KWM) in comparison to the rote learning method (RLM) for the learning of English collocations. A controlled laboratory-like setting was adopted for randomly assigning participants to the KWM group (n = 15) or the RLM group (n = 15). After receiving training on the use of the respective strategy, the two participant groups applied the respective strategy to the learning of collocations. Collocations were assessed at three different time periods, and additional data regarding perceptions of the two strategies were elicited through one-on-one post hoc interviews. The quantitative data revealed that the KWM was superior to the RLM in terms of the long-term retention of productive collocation knowledge; knowledge of adjective–noun collocations was retained better than verb–noun collocations. The qualitative data revealed that participants deemed that the KWM was unfamiliar but effective. Additionally, participants claimed that the RLM was facile but may result in a high rate of forgetting. The pedagogical implications are that foreign language teachers should encourage language learners to use the KWM for learning English collocations. Although the KWM has been recommend by many researchers, it is still rarely advocated for by foreign language instructors. Therefore, it is important that both EFL learners and teachers should be aware of the KWM’s long-term retention effects on the learning of English collocations and apply this vocabulary learning strategy (VLS) in their actual learning and teaching context.