OAuth is a secure authorization framework that allows users to grant third-party applications limited access to their online accounts without sharing their passwords. For example, when you use your Google account to log into a different app, OAuth lets that app access your basic information while keeping your password safe. This process works by using tokens instead of passwords. When you authorize an app, OAuth provides it with a token that represents your permission. This way, the app can perform specific actions on your behalf, like posting on Twitter or accessing your Dropbox files, without compromising your account security.