Background: COVID-19 vaccine booster dose hesitancy amongst the Saudi Arabia population is a concern. The objectives of the study were to explore the Saudi public’s willingness to receive a COVID-19 vaccine booster dose and identify the factors affecting their willingness. Methods: From December 2021 to March 2022, an online cross-sectional survey using an anonymous, structured, and self-administered questionnaire was conducted among members of the Saudi public aged ≥18 years who did not receive a COVID-19 vaccine booster dose. Results: Of the 2101 respondents, 86.8% expressed a willingness to receive a COVID-19 vaccine booster dose. Multiple logistic regression analysis showed that age (18 to 25 years) (adjusted odds ratio [aOR] = 2.54; 95% confidence interval [95% CI] = 1.14–5.74), being single (aOR = 2.85; 95% Cl = 1.42–5.72), and prior receipt of an influenza vaccine (aOR = 2.45; 95% Cl = 1.80–3.34) were significantly associated with participants’ willingness to receive the COVID-19 vaccine booster dose. Having a bachelor’s degree or above (aOR = 0.95; 95% CI = 0.81–0.99) and not following COVID-19 news (aOR = 0.70; 95% CI = 0.52–0.89) were associated with a significant likelihood of having no intention to receive the COVID-19 vaccine boosters. Conclusions: Most Saudi people were willing to have the COVID-19 vaccine booster dose, with age and prior influenza vaccination as the predictors; paradoxically, a university-level qualification was a barrier.