Malnutrition has many associated physiological and psychological consequences for older adults that can result in reduced quality of life, poor disease outcomes and more frequent and longer hospital stays. Early recognition of malnutrition allows for timely intervention and treatment. There are several screening tools for nutrition risk. The most common one for malnutrition developed and validated for older adults is the short-form of the Mini Nutritional Assessment (MNA-SF). It can be completed in just a few minutes and applied in all health care settings. This systematic review and meta-analysis serves to synthesise the totality of evidence regarding the diagnostic accuracy of the MNA-SF tool compared with the full-form of the Mini Nutritional Assessment (MNA-FF) in older adults for the diagnosis of malnutrition in healthcare settings. Systematic searches of five bibliographical databases will be performed and will include the Pubmed, EMBASE, Cochrane Library, CINAHL and Web of Science to identify all studies that validate the MNA-SF for malnutrition among older adults in healthcare settings. Risk of bias will be assessed with the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Pre-specified MNA-SF scores will be used to identify patients’ risk of malnutrition. Using data from 2x2 tables, studies will be pooled to generate summary estimates of sensitivity and specificity using a bivariate random effects model. The findings of this systematic review of diagnostic accuracy will provide evidence for healthcare professionals to make informed decisions regarding the optimum use of the MNA-SF as a nutrition risk screening tool to identify malnutrition among older people. Registration details: Prospero registration number CRD42019131847