Purpose: The purpose of this article was to examine how different types of learning experiences affect naming impairment in aphasia. Methods: In 4 people with aphasia with naming impairment, we compared the benefits of naming treatment that emphasized "retrieval practice" (practice retrieving target names from long-term memory) with "errorless learning" (repetition training, which preempts retrieval practice) according to different schedules of learning. The design was within subjects. Items were administered for multiple training trials for retrieval practice or repetition in a "spaced" schedule (an item's trials were separated by multiple unrelated trials) or "massed" schedule (1 trial intervened between an item's trials). In the spaced condition, we studied 3 magnitudes of spacing to evaluate the impact of effortful retrieval during training on the ultimate benefits conferred by retrieval practice naming treatment. The primary outcome was performance on a retention test of naming after 1 day, with a follow-up test after 1 week. Results: Group analyses revealed that retrieval practice outperformed errorless learning, and spaced learning outperformed massed learning at retention test and at follow-up. Increases in spacing in the retrieval practice condition yielded more robust learning of retrieved information. Conclusion: This study delineates the importance of retrieval practice and spacing for treating naming impairment in aphasia.