Retrieval practice refers to the act of retrieving information from memory with the intent to promote learning. Although retrieval practice is often operationalized as taking a test, it can occur through many different types of learning activities (e.g., answering a question posed by a teacher, working on a practice problem, writing an essay, using flashcards, having a group discussion). Research on retrieval practice has a long history, but there has been a surge of interest since 2005 in the phenomenon. This large body of research has shown that retrieval practice produces superior long-term retention and transfer of learning to new contexts relative to activities that are predominantly used to study material (e.g., listening to a lecture, reading a textbook, watching a video)—a finding that is commonly referred to as “the testing effect.” Importantly, it is the act of retrieving that causes learning; such direct effects of retrieval practice can be distinguished from its indirect effects on learning. These indirect effects include: providing formative feedback to the learner, incentivizing study, and reducing test anxiety. Research has also identified several factors that moderate the effects of retrieval practice, including experimental design, test format, provision of feedback, and retention interval. In addition, there is ample evidence to support the conclusion that the benefits of retrieval practice are highly generalizable across learner populations, materials and skills, settings, and outcome measures. Given that the mnemonic benefits of retrieval practice are robust and generalize broadly, it is widely recommended as a learning strategy for students and a pedagogical technique for educators.