<p>Metacognitive monitoring, or the capacity to assess and regulate one’s cognitive activities, is essential for maintaining optimal mental functioning. Metacognitive monitoring may be particularly important for individuals as they age, fostering self-awareness of cognitive strengths and limitations, guiding strategy selection to enhance performance, compensating for age-related changes to cognitive abilities, and identifying the earliest cognitive symptoms of disease. By evaluating one’s own understanding, individuals can align their confidence with actual ability, promoting better decision making and behavioral control. This review synthesizes the current literature on age-related differences in the accuracy of metacognitive monitoring across different types of metacognitive judgments, including judgments of learning, feelings of knowing, and post-decision confidence. We begin by discussing two key components of metacognitive monitoring: metacognitive sensitivity and metacognitive calibration. Then, we examine existing studies to address two main questions: whether age-related differences in one component (e.g., metacognitive calibration) can be explained by variations in the other (e.g., metacognitive sensitivity), and whether these differences can be attributed to age-related changes in underlying cognitive or perceptual processes. We find that the current literature does not provide definitive evidence for or against the decline of metacognitive monitoring in older adults. Rather, findings suggest that aging may differentially affect metacognitive accuracy depending on the type of judgment and task demands, with some domains showing preserved or even enhanced performance. These mixed findings underscore the conceptual and methodological complexity of studying metacognition in aging. We conclude by outlining key theoretical and empirical directions to clarify mechanisms and advance the field.</p>