One of the most important reasons to investigate human metacognition is its role in directing how people study. However, limited evidence exists that metacognitively guided study benefits learning. Three experiments are presented that provide evidence for this link. In Experiment 1, participants' learning was enhanced when they were allowed to control what they studied. Experiments 2a-d replicated this finding and showed contributions of self-regulated study to learning. Experiments 3a and 3b showed that, when forced to choose among items they did not know, participants chose the easiest items and benefited from doing so, providing evidence for the link between metacognitive monitoring/control and learning, and supporting the region of proximal learning model of study-time allocation.