This study investigated the relationship between phonological memory and second language (L2) fluency gains in native English-speaking adults learning Spanish in two learning contexts: at their home university or abroad in an immersion context. Phonological memory (operationalized as serial nonword recognition) and Spanish oral fluency (temporal/hesitation phenomena) were assessed at two times, 13 weeks apart. Hierarchical regressions showed that, after the variance attributable to learning context was partialed out, initial serial nonword recognition performance was significantly associated with L2 oral fluency development, explaining 4.5-9.7% of unique variance. These results indicate that phonological memory makes an important contribution to L2 learning in terms of oral fluency development. Furthermore, these results from an adult population extend conclusions from previous studies that have claimed a role for phonological memory primarily in vocabulary development in younger populations. [Additional funding for this research was provided by the Fonds de recherche en sante du Quebec.]