Almost anything worth doing takes effort, so it is no surprise that effort has played such a central role in how researchers, theoreticians, instructors, and even students think about student learning and achievement. In this special issue, the authors of the target articles explore the importance of effort to students' self-regulated learning within multiple domains. To further support research progress on effort, we distinguish between objective effort as a direct causal agent of learning gains and effort as a student perception. We argue that understanding effort as a student perception shows promise for discovering ways to improve self-regulated learning and student achievement. In developing these arguments, we consider the contribution of the target articles to five themes relevant to metacognitively driven self-regulated learning, with the aim of fostering progressive research programs aimed at revealing the potential roles of effort in student achievement.