In this paper we examine the contributions of metacognitive and self-regulated learning theories to research on students' calibration of comprehension. Historically, cognitive psychologists have studied calibration of comprehension within a purely metacognitive framework, with an emphasis on the role of text and task factors but little consideration of factors of self. There has been a recent trend, however, towards incorporating a social cognitive perspective to the study of calibration of comprehension, with factors of self such as motivation and affect being examined more often. Among the factors of self that have been examined, self-efficacy has played a major role as it may be all but impossible to disentangle its influence on students' calibration of comprehension. Other variables of self that have been examined include ability, familiarity, ego and goal-orientation, goal setting, personality traits and susceptibility to social and cultural influences. Broadening the context in which calibration of comprehension is assessed allows a more complete examination of the rich set of interrelated processes that affect students' performance.