This study systematically assesses the literature pertaining to the diagnostic test accuracy of assessment instruments to evaluate patients following hip fracture surgery who present with cognitive impairment. A systematic review and meta-analysis was performed. Studies assessing the reliability, validity, sensitivity or specificity of assessment tools for patients following hip fracture who were cognitively impaired were included. An assessment of published (MEDLINE, EMBASE, CINHAL, AMED, Cochrane library, PEDro) and unpublished/trial registry (OpenGrey, the WHO International Clinical Trials Registry Platform, Current Controlled Trials, the UK National Research Register Archive) databases were undertaken. Methodological quality of the literature was assessed using the QUADAS-2 appraisal tool. Nine studies including 690 participants, with a mean age of 82.1 years were included. The literature demonstrated a high risk of bias for study methodology, but low risk of bias for applicability. Two assessment domains were recognized: pain and delirium. For pain, the Facial Action Coding System (FACS) and DOLOPLUS-2 tools possessed strong inter-rater reliability and internal consistency, with the FACS demonstrating concurrent validity with other pain scales. For delirium, the Delirium Rating Scale-Revisited-98 (DRS-R-98) demonstrated high inter-rater reliability and sensitivity and specificity, with the NEECHAM Confusion Scale possessing high internal consistency. To conclude, there is a paucity of literature assessing the reliability, validity and diagnostic test accuracy of instruments to assess people with cognitive impairment following hip fracture surgery. Based on the current available data, delirium may be best assessed using the NEECHAM Confusion Scale or DRS-R-98. Pain is most accurately evaluated using the FACS.