As the field of heritage language acquisition expands, there is a need for proficiency to compare speakers across groups and studies. Elicited imitation tasks (EITs) are efficient cost-effective tasks with a long tradition in proficiency assessment of second language (L2) learners, first language children, and adults. However, little research has investigated their use with heritage speakers (HSs), despite their oral nature, which makes them appropriate for speakers with variable literacy skills. This study is a partial replication of Solon, Park, Dehghan-Chaleshtori, Carver & Long (2022), who administered an EIT originally developed for advanced L2 learners on a group of HSs. In this study, we administered the same EIT with minor modifications to 70 HSs and 132 L2 learners of Spanish with different levels of proficiency and ran a Rasch analysis to evaluate the functioning of the task with the two groups. To obtain concurrent validity evidence, scores on the EIT were compared with participants’ performance in an oral narration; evaluated for complexity, accuracy, and fluency (CAF); and compared with a standardized oral proficiency test, the Versant Spanish Test. Results of Rasch analyses showed that the EIT was effective at distinguishing different levels of ability for both groups, and analyses showed moderate to strong correlations between CAF measures and the EIT and very strong correlations between the EIT and the Versant Spanish Test. These results provide evidence that the EIT is an efficient and adequate proficiency test for HSs and L2 learners of Spanish; its use in research settings is recommended.