Measuring sleep and sleep quality is an important diagnostic and monitoring tool, and a number of different methods for measurement have been developed over the last half-century. Two prevalent methods include wrist actigraphy and sleep diaries. Both methods can be applied in different circumstances, but both have strengths and weaknesses. This study aimed to identify the extent to which there is congruence in the scores achieved by each method of sleep measurement. Sixty-eight respondents were asked to wear a wrist actigraphy and complete a sleep diary over the course of five days. There was a significant difference between the mean scores achieved using each measurement method, with actigraphy scores indicating lower total sleep time (TST) than diaries. However, this difference was not consistently present when the scores were compared on a day by day basis. Participant adherence is likely to fluctuate over the course of a sleep study and may undermine the accuracy of sleep diaries.