There is a lack of studies evaluating frailty and physical activity in people aged 100 years or older. This review aimed to synthesize the evidence on frailty and physical activity in centenarians. A systematic review was conducted according to the PRISMA guidelines. We searched the PubMed, CINAHL, SCOPUS, Web of Science, and Lilacs databases for articles published until 18 June 2020. This review was registered with PROSPERO (CRD42020162913). Five studies were included in this review according to the eligibility and exclusion criteria. In summary, the reviewed studies show that centenarians are fragile and that frailty increases with age; however, women are frailer than men. The most common frailty criteria were low physical activity level (78% to 72.5%), muscle weakness (84.2% to 66%), and slow walking speed (77.6% to 48.4%). Most centenarians perform less exercise than younger older adults, have a low physical activity level, live in nursing homes, and exhibit functional disability. Regarding the methodological quality of the studies, one article was classified as regular and the other four as poor. Frailty and a low physical activity level are common in centenarians. Experimental studies with better methodological quality are necessary to better understand the causal relationship between variables.