Background: Cyberchondria is a recent phenomenon characterized by the excessive/frequent searching of the internet for health-related information (HRI) that results in concerns/anxiety over health and wellness. Studies have shown an increase in the prevalence of cyberchondria and that it is associated with smartphone addiction and eHealth literacy, but few such studies are available from Saudi Arabia. Methods: This cross-sectional study included adult Saudis living in Jeddah, Saudi Arabia, and was conducted between May 1 and June 30, 2022. A four-section questionnaire was distributed using Google Forms, and included the Cyberchondria Severity Scale (CSS), Smartphone Addiction Scale-Short Version (SAS), and Electronic Health Literacy scale (eHEALS). The scales were translated into Arabic using the forward–backward technique, and then evaluated for content validity, face validity, and reliability. Results: The reliability of the translated versions was satisfactory: CSS Cronbach’s alpha = 0.882; SAS = 0.887; eHEALS = 0.903. A total of 518 participants were inlcuded, of which the majority were female (64.1%). The prevalence of cyberchondria was 2.1% (95% CI: 1.1–3.8), 83.4% (79.9–86.5), and 14.5% (11.6–17.8) for low, moderate, and high grades, respectively. Two-thirds of the participants (66.6%) had smartphone addiction, while three-fourths (72.6%) had a high level of eHealth literacy. There were significant correlations between cyberchondria and smartphone addiction ( r = 0.395, CI = 0.316/0.475, P = 0.0001) and high eHealth literacy ( r = 0.265, CI = 0.182/0.349, P = 0.0001). Conclusion: The study revealed a high prevalence of cyberchondria in a Saudi population, and this was associated with smartphone addiction and high eHealth literacy.