Background/Objectives: Frailty syndrome favors the deterioration of health; therefore, identifying associated factors is essential for establishing preventive measures. Oral candidiasis is a factor that may be related to the onset of frailty. Our objective was to evaluate the association between frailty and oral candidiasis in institutionalized participants. Methods: We conducted a cross-sectional study involving 589 institutionalized individuals aged 65 years or older. A diagnosis of candidiasis was established clinically and with a microbiological study (potassium hydroxide (KOH) test and culture for candidiasis). Assessments of salivary flow and the use of dental prostheses were also performed. Frailty was classified according to Fried’s phenotype criteria. Results: Frailty and prefrailty were found in 28.9% and 66.7% of the participants, respectively. Oral candidiasis was diagnosed in 39.05% of cases and was more frequent among individuals with dental prostheses (49.13%) and hyposalivation (47.54%). Conclusions: Our findings suggest that frailty in institutionalized older adults is associated with the presence of subprosthetic stomatitis associated with candidiasis and hyposalivation, indicating the need for integrated oral health strategies in geriatric care.