While an elicited imitation test (EIT) has been widely used as a measure of oral proficiency in second language acquisition (SLA) research, it is still unclear the extent to which memory capacity impacts EIT performance. In light of this gap, the present study sought to clarify the nature of elicited imitation by examining the relative contributions of language ability and phonological short-term memory (PSTM) to EIT performance. Seventy-eight second language (L2) learners of Spanish, who were grouped into 3 Spanish experience levels, took a Spanish EIT, an L2 oral narrative task, and a nonword repetition (NWR) task in their first language. Results demonstrated that learners' EIT performance was primarily predicted by complexity, accuracy, and fluency (CAF) measures extracted from the oral narrative task rather than NWR scores, which served as an index for PSTM capacity. Furthermore, the present study provided suggestive evidence that PSTM capacity may differentially mediate EIT performance depending on the extent of learners' proficiency in and experience with Spanish. While facilitative effects for PSTM capacity were observed for less experienced learners, no effects were found for more experienced learners.