This systematic review and meta-analysis generates evidence of the prevalence and associated factors of common mental disorders (i.e., depression, anxiety, and stress) related to the pandemic among the Saudi general population. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a comprehensive literature search was performed in the respective databases (e.g., PubMed, Scopus, Web of Science), from 22 July to 17 August 2021, and identified a total of 220 articles. Adhering to the inclusion criteria (i.e., original research concerning the prevalence and/or associated factors of depression and/or anxiety and/or stress disorders among the general Saudi population, published in English peer-reviewed journals), 15 studies were included in this review which consisted of a total of 262,656 participants. The overall prevalence of depression, anxiety, and stress was 30% (95% confidence interval [CI]: 22% to 38%, I² = 99.58%), 20% (95% CI: 16% to 24%, I² = 99.32%), and 29% (95% CI: 11% to 47%, I² = 99.76%), respectively. Risk factors of mental health problems were found to be female sex, younger age group, single/divorced marital status, lower education, lower income, non-Saudis, unemployment status, students, being in a small family and living with elderly of the sociodemographic factors. Smokers, less physical activities, lower resilience, reduced immune status, chronic health problems, and psychiatric illness history were associated with a higher degree of mental health problems. In addition, coronavirus disease 2019 (COVID-19)-related risk factors of mental illness included lack of knowledge, fear, worry and concern, family member or friends’ infection or death, lockdown restrictions, quarantine, confirmed or suspected of COVID-19 infection, and even pandemic effects. In conclusion, appropriate mental health preventive approaches for the Saudi general people are highly needed, where this review can be worthy of help by providing in detailed information to the respective authorities.