The 2018 Colorado State Senate elections took place as part of the biennial United States elections. Colorado voters elected state senators in 17 of the 35 districts in the state senate. State senators serve four-year terms in the Colorado State Senate. The Colorado Reapportionment Commission provides a statewide map of the state Senate here, and individual district maps are available from the U.S. Census here.

Leroy Garcia is an American politician who served in the Colorado Senate from the 3rd district, from 2019 to 2022, as a member of the Democratic Party. He served as the president of the state senate from 2019 until his 2022 resignation to join the department of defense, and previously served as the Minority Leader from 2018 to 2019. Before his tenure in the state senate he served in the Colorado House of Representatives from the 46th district from 2013 to 2015, and on the city council in Pueblo, Colorado.