Constitution Day is a civic observance celebrated in many countries to commemorate the adoption, signing, or enactment of a nation's constitution—the foundational legal document that defines the structure of government, the rights of citizens, and the rule of law.

A constitution is a formal document that establishes the framework of government, defines the separation of powers, guarantees individual rights and freedoms, and provides the legal basis for all other laws.

It often represents a country's core values, historical struggles, and vision for the future.