In most post-secondary Spanish language programs in the U.S., heritage language (HL) learners and second-language (L2) learners are enrolled together, in the same courses (Ingold, Rivers, Tesser, & Ashby, 2002). Nevertheless, there is scant empirical research on what actually goes on in these classrooms and what the nature of learner-learner interactions is (Blake & Zyzik, 2003; Bowles, in press). This study reflects a reality in many Spanish classes because it analyzes the task-based interactions of nine learner-learner pairs, each containing an L2 learner and an HL learner of Spanish. The pairs completed a series of three tasks--one oral (a spot-the-differences task) and two written (a crossword puzzle task and a cloze/complete-the-story task). Results showed that, in completing the tasks, the L2 and HL learners had their language-related issues resolved in equal proportion but that there were qualitative differences on the written tasks in terms of the linguistic targets. HL learners relied on their L2 partners for orthography issues (spelling and accent placement), whereas L2 learners relied on their HL partners for vocabulary issues and, to a lesser extent, for grammar-related queries. Implications for pedagogy in classrooms enrolling both L2 and HL learners are discussed. (Contains 1 note, 7 tables, and 3 figures.)