The Second Amendment to the United States Constitution provides for the right to keep and bear arms, and reads: "A well regulated militia being necessary to the security of a free state, the right of the people to keep and bear arms shall not be infringed."

Some people believe this language creates a Constitutional, individual right for citizens of the United States to keep and bear arms, and prohibits Congress and state legislatures from prohibiting or restricting the possession of firearms.

Others believe the beginning words ("A well regulated militia being necessary”) indicate the intent of the Amendment was only to restrict Congress from limiting a state’s right to self-defense. This collective rights theory of the Second Amendment holds that citizens do not have an individual right to possess firearms, and that federal, state, and local legislative bodies may regulate the possession of firearms without implicating a Constitutional right.

At the time the First Amendment was ratified, some militia members used their own weapons, and some used weapons from their state’s militia stores.

In Colorado, as in the rest of the United States, the Second Amendment to the U.S. Constitution is the foundational legal provision that protects the right to keep and bear arms. The interpretation of the Second Amendment has been subject to debate, with some advocating for an individual rights approach, which asserts that the Amendment guarantees a personal right to firearm possession and use, and others supporting a collective rights approach, which suggests the right is linked to state militia service. The U.S. Supreme Court, in decisions such as District of Columbia v. Heller (2008), has upheld the individual rights interpretation, affirming that the Second Amendment protects an individual's right to possess a firearm unconnected with service in a militia, and to use that arm for traditionally lawful purposes, such as self-defense within the home. Colorado state statutes reflect this interpretation and provide for the right of individuals to keep and bear arms, subject to certain regulations designed to promote public safety. These regulations include background checks for private gun sales, a ban on high-capacity magazines, and laws concerning the carrying of concealed weapons. However, Colorado does not require a permit to purchase a gun, nor does it have a firearm registry or require a license to own a gun.