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.This study was conducted by the first author as part of her doctoral dissertation research, under the supervision of Norman Segalowitz. The research was funded by a grant to Barbara Freed from the Council for International Educational Exchange (New York), in part by a grant from the Natural Sciences and Engineering Research Council of Canada to Norman Segalowitz, in part from the Dean's Office, Faculty of Arts and Science at Concordia University to Norman Segalowitz, and in part from the Fonds de recherche en santé du Québec to Irena O'Brien. The authors wish to thank Manuel Díaz-Campos, Barbara Lafford, and Nicole Lazar, who were members of the research team involved in the larger project of which this study is one part. The authors would also like to thank Peter Scherzer, Leif French, and two anonymous SSLA reviewers for their helpful comments on an earlier draft of this article. Finally, the authors would like to thank Conchita Bueno, Hazel Casas, Elizabeth Gatbonton, Randall Halter, Guy Lacroix, Anne-Marie Linnen, Magnolia Negrete, Laura Renteria-Díaz, Marlene Taube-Schiff, and Naomi Yamasaki, who helped during various phases of this project.