Within the educational psychology literature there is an abundance of research in the field of metacognition. The concentration of this research however has been in primary and secondary school contexts with little attention given to tertiary students' understanding or use of metacognition; there has been even less attention to whether age is a factor in tertiary students' perceptions of their metacognitive processes. The primary purpose of this study was to explore the perceptions of two distinct groups of first year university students, towards their understanding and usage of metacognitive processes and strategies. The two groups defined were traditional school leavers and mature age students. The findings from the exploration of these perceptions were compared to ascertain the similarities and differences in metacognitive processes between the two cohorts. The data collected for this study were obtained through a process of individual face-to-face in- depth interviews. The choice of this methodology was deliberate in order to gather rich data about the students' perceptions and experiences rather than attempt to measure their levels of metacognition against some predetermined standard. Data were collected and analyzed on the two constructs of metacognition which were identified in the literature search. These were metacognitive knowledge and metacognitive control. A range of affective variables such as self efficacy, motivation and expectancy of success, which impact on students' metacognitive abilities and processes, were also considered in the data collection and analysis. The findings indicated that age was a factor in determining some differences and similarities in students' perceptions of their own and others metacognitive processes. In certain cases the traditional school leavers' recency of experience with formal study was deemed an advantage; in others the life experience of the mature age students was perceived an advantage. In some instances the age of the student had no discernable impact on their understanding of, and ability to, utilize metacognitive strategies. These findings assist to broaden the understanding of student perceptions of metacognition in the tertiary context. The findings also make it imperative that tertiary institutions make fewer assumptions about the skills and abilities of their commencing students based on the criterion of age and offer more opportunities to assist students to understand the value of developing and improving their metacognitive processes.