In many countries around the world, religiosity among people is still strong and gives meaning to life. The chapter investigates how different facets and components of religiosity are associated with risky behaviors, such as smoking, excessive alcohol consumption, substance use, psychological distress, risky sexual behaviors, and HIV-related risky habits among young and old adults in various countries, cultures, or religions. This comprehensive review of a growing body of evidence highlights the positive, neutral, or negative influences of religiosity in mitigating these health risk habits. In the vast majority of cases reviewed, religiosity significantly promotes a healthy lifestyle by reducing or eliminating various harmful and addictive behaviors.