A restriction is a specific type of rule that defines a finite (and generally absolute) boundary defined for a type of process or function.

Restriction may also refer to:

• Restriction enzyme, the restriction of the rule of sensibility of bacteria to phages.
• Restrictions (album), an album by American hard rock band Cactus.

In mathematics:

• Restriction (mathematics), a type of function used in the context of sheaves
• A restriction of a function
• A

In economics:

• A type of boundary or regulation placed on the trade of certain goods or services
• A condition on the variables in statistics, econometrics, and regression analysis

The adjectival form, "restricted," may be used in reference to written or unwritten covenants enforcing racial or ethnic segregation or religious segregation  frequently anti-Jewish or more generally anti-Semitic  in housing (see "Restrictive covenant") or in organizations, such as country clubs.