We investigated the benefits of two ways to use flashcards to perform retrieval practice: alone versus with a partner. In three experiments, undergraduate students learned word-definition pairs using flashcards alone (Individual condition) or with another student (Paired condition). Participants then made global judgments of learning (gJOLs; Experiments 1-3), and item-level judgments of learning (iJOLs; Experiment 3). Finally, participants took a cued-recall test after a 5-min delay (Experiments 1-3) and a 24-h delay (Experiments 2-3). In Experiment 1, students in the Paired condition dropped flashcards less often than in the Individual condition (dropping was prohibited in Experiments 2-3). In addition, although final test performance tended to be similar across conditions, inaccurate gJOLs for the immediate test--inflated by ~ 20% relative to actual immediate test performance--were common in the Individual condition but not in the Paired condition in Experiments 1-2. In Experiment 3, we tested whether this difference in metacognitive calibration was due to the Paired condition requiring overt retrieval by instructing participants in the Individual condition to retrieve out loud. With this change, participants in the Individual and Paired conditions reported similarly accurate gJOLs and iJOLs. Taken together, these findings suggest that although performing retrieval practice with flashcards alone versus with a partner yields comparable amounts of learning, doing so with a partner can increase metacognitive accuracy, a benefit possibly driven by the facilitation of overt retrieval. Overall, these findings have implications for self-regulated learning and effective exam preparation.