Working memory (WM) plays an important role in language learning processes. Several studies have focused on WM and, more specifically, on one of its subcomponents, the phonological loop (and its relationship with the second language [L2]). Thus, the present research aims to review studies on phonological loop and L2 acquisition, carrying out a survey on their data-gathering instruments, as well as their results. Regarding language acquisition, the results of the reviewed studies indicated that WM correlates positively with first language (L1) and L2, considering 1. vocabulary acquisition, 2. grammar acquisition, 3. language proficiency, 4. phonological processing, 5. storage capacity, and 6. attention.