Access control models are frameworks that define how users can access resources within a system. These models help organizations manage permissions and ensure that only authorized individuals can view or modify sensitive information. Common models include Discretionary Access Control (DAC), where resource owners decide access, and Mandatory Access Control (MAC), which enforces strict policies set by the system. Another important model is Role-Based Access Control (RBAC), where access rights are assigned based on user roles within an organization. This simplifies management by grouping users with similar responsibilities. Each model serves different security needs, helping to protect data and maintain privacy.