This study explores the relationship between aptitude, phonological memory (PM), and second language (L2) proficiency in nonnovice adult learners of English as an L2. Native speakers of French (N = 77) enrolled in a university Teaching English as a Second Language program were the participants in the study. Exploratory factor analysis revealed three main factors corresponding to the variables examined: L2 proficiency, aptitude, and PM. Multiple regression analyses revealed aptitude subtests and PM together predicted 29% of the variance in L2 proficiency. Additional regression analyses carried out on lower and higher proficiency subgroups, created by a median split on proficiency scores, revealed that none of the variables predicted L2 proficiency in the higher proficiency subgroup. PM remained as a significant predictor for the lower proficiency subgroup, extending the pattern of results found elsewhere in younger populations to adult nonnovice L2 learners.