OpenID Connect is an identity layer built on top of OAuth2. It allows for secure authentication and single sign-on (SSO) across multiple applications. OpenID Connect provides a standardized way to verify the identity of users based on authentication performed by an identity provider. It is widely used in cloud services and enterprise applications to streamline user login processes. OpenID Connect supports features like user profile retrieval and multi-factor authentication (MFA), enhancing both security and user experience.