Objectives: The objectives of this study were to determine the prevalence of frailty in the context of atrial fibrillation (AF); to identify the most commonly used frailty instruments in AF; and to describe the effect of frailty on non-vitamin K oral anticoagulant (NOAC) prescription for stroke prevention in adults with AF. Methods: A systematic search of databases, including Medline, Embase, Web of Science, Cochrane Library, Scopus, and CINAHL, was conducted using search terms including “atrial fibrillation,” “frailty,” and “anticoagulation.” A narrative synthesis was undertaken. Results: A total of 92 articles were screened, and 12 articles were included. The mean age of the participants (n = 212,111) was 82 years (range = 77–85 years) with 56% of participants identified as frail and 44% identified non-frail. A total of five different frailty instruments were identified: the Frailty Phenotype (FP; n = 5, 42%), the Clinical Frailty Scale (CFS; n = 4, 33%), Cumulative Def