This study investigates the effectiveness of three methods of learning vocabulary among 778 beginning second language (L2) learners. Rote memorization consists of memorizing the first language (L1) translation of a new L2 word by rehearsal. Semantic mapping displays L1 words conceptually related to the L2 word in a diagram. The keyword method involves associating the novel L2 word with an L1 keyword that is acoustically or orthographically similar, and then connecting the L1 keyword with the L1 translation of the L2 word. The results reveal that vocabulary learning techniques requiring deeper processing through form and meaning associations (i.e., the keyword method) yield the best retention. In addition, rote memorization of L1–L2 equivalents is more effective than creating multiple meaning associations (i.e., semantic mapping). We suggest that using the keyword method with phonological keywords and direct L1 keyword-translation links in the classroom leads to better L2 vocabulary learning at early stages of acquisition.