Identifying the factors driving vaccine hesitancy can improve vaccine attitudes and motivate individuals to have the recommended vaccinations. However, failure to address the issue directly, or worse, ignoring it, could deepen such concerns, resulting in lower vaccination rates, leading to elevated rates of illness and vaccine-preventable deaths among older adults. The aim of this study was to explore the rate of acceptance of the COVID-19 vaccine among older adults in Saudi Arabia, along with the associated predicting factors and reasons for hesitancy. This study extracted data from a cross-sectional online survey on the acceptability of COVID-19 vaccination in Saudi Arabia, which was conducted from 8 to 14 December 2020. The sample of the study included 488 older adults aged 50 and older. The major data analytic tools employed in the study were bivariate and multivariable regression analyses. Among the 488 participants, 214 (43.85%) reported willingness to accept the COVID-19 vaccine when available. Older men were more likely to be willing to be vaccinated (adjusted odds ratio (aOR): 2.277; 95% confidence interval (CI): 1.092-4.745) than older women. High levels of education were significantly associated with willingness to be vaccinated. Older adults who had previously refused any vaccine were less likely to take the COVID-19 vaccine (aOR: 0.358; 95% CI: 0.154-0.830). Those who expressed a high or very high level of concern related to becoming infected were more likely to accept the vaccine against COVID-19 (aOR: 4.437; 95% CI: 2.148-9.168). Adverse side effects (27.01%), and safety and efficacy concerns (22.63%) were the most commonly cited reasons for vaccine hesitancy. The vaccination acceptance rate among older adults in Saudi Arabia is low. Interventions designed specifically for older adults addressing worries and concerns related to the vaccine are of paramount importance. In particular, these interventions should be tailored to address gender-based and health literacy level differences.