List of Colorado ballot measures

The U.S. state of Colorado has had a system of direct voting since gaining statehood in 1876. Citizens and the Colorado General Assembly both have the ability to place new legislation, those recently passed by the General Assembly, and constitutional amendments on the ballot for a popular vote. Colorado has three types of ballot measures that can be voted on in a statewide election: initiatives, referendums, and legislatively referred measures. In order to be placed on the ballot, supporters of a measure must gather signatures from registered voters. From 1877 to 1910, the only ballot measures allowed were legislatively referred measures. In 1910, Referendum 3 was placed on the ballot by the General Assembly and passed, creating a citizen-led process for initiatives and referendums. The first successful citizen-initiated measures were passed in 1912.

Since that time, ballot measures have played a major role in Colorado politics. After Denver was awarded the hosting rights to the 1976 Winter Olympics, citizens moved to block funding the games with a ballot measure in 1972. A 1990 ballot measure instituting term limits for many elected officials helped galvanize a nationwide movement for term limits, and 2000's Amendment 20 legalized the medical use of marijuana. That measure was followed by full decriminalization in 2012 and the decriminalization of psilocybin mushrooms in 2022.