Background The purpose of this study was to determine if a deficit in metamemory could account for the disparity between subjective and objective measures of memory function commonly observed in patients with breast cancer (BC). Metamemory refers to the awareness and management of one's own memory function. It is considered an aspect of executive functioning, one of the most common areas of cognitive compromise associated with BC and its treatment. Methods Fifty‐four women with early stage BC who had recently completed chemotherapy were compared with 54 healthy women matched on age and education. Cognitive function was objectively assessed with a neuropsychological test battery and subjectively assessed with the Functional Assessment of Cancer Therapy Cognitive Scale. Metamemory was assessed with a Feeling of Knowing (FOK) paradigm. Results The patients with BC scored significantly lower than the controls on both the objective and subjective cognitive measures, as well as on free recall and recognition conditions of the FOK, suggesting some decline in primary memory functions such as working memory, encoding, and retrieval. The discrepancy between the objective and subjective measures was larger in the patients with BC than in the controls, but there was no difference between the groups on the FOK metamemory index. Conclusions Discrepancy in objective and subjective measures of cognition in patients with BC cannot be accounted for in terms of a deficit in meta‐cognition. Objective and subjective measures are complementary, and a comprehensive cognitive assessment in patients with BC requires both. Copyright © 2015 John Wiley & Sons, Ltd.