BackgroundManagement of mental workload is a key aspect of safety in anaesthesia but there is no gold-standard tool to assess mental workload, risking confusion in clinical and research use of such tools.ObjectiveThis review assessed currently used mental workload assessment tools.MethodsA systematic literature search was performed on the following electronic databases; Cochrane, EMBASE, MEDLINE, SCOPUS and Web of Science. Screening and data extraction were performed individually by two authors. We included primary published papers focusing on mental workload assessment tools in anaesthesia.ResultsA total of 2331 studies were screened by title, 32 by full text and 24 studies met the inclusion criteria. Six mental workload measurement tools were observed across included studies. Reliability for the Borg rating scales and Vibrotactile device was reported in two individual studies. The rest of the studies did not record reliability of the tool measurements used. Borg rating scales, NASA-TLX and task-oriented mental work load measurements are subjective, easily available, readily accessible and takes a few minutes to complete. However, the vibrotactile and eye-tracking methods are objective, require more technical involvement, considerable time for the investigator and moderately expensive, impacting their potential use.ConclusionWe found that the measurement of mental workload in anaesthesia is an emerging field supporting patient and anaesthetist safety. The self-reported measures have the best evidence base.