Rep. Jared Polis (D) defeated state Treasurer Walker Stapleton (R), Bill Hammons (Unity), and Scott Helker (L) in the general election on November 6, 2018, for governor of Colorado.

Incumbent Gov. John Hickenlooper (D) was prevented by term limits from seeking a third term, leaving the seat open. Of the ten preceding gubernatorial elections, a Democratic candidate won eight—including Hickenlooper's victories in 2010 and 2014—and a Republican candidate won two. Hillary Clinton (D) carried the state in 2016 by a margin of 5 percentage points. As of November 2018, three race rating outlets rated the race Leans Democratic.

Polis' victory, alongside Democrats gaining a majority in the state senate, created a Democratic trifecta in Colorado. At the time of the 2018 election, Colorado had been under divided government since Democrats lost their state senate majority in the 2014 elections.

As a result of the 2018 elections, Democrats gained a triplex (control of the governorship, attorney general office, and secretary of state office) in Colorado. The attorney general and secretary of state offices had been held by Republicans in 2018.

The winner of this election stood to influence the state's redistricting process following the 2020 census. Under Colorado state law, the governor has the power to veto congressional district proposals put forward by the state legislature. The governor is also responsible for appointing three of the 11 commissioners to the board responsible for drawing state legislative districts.

Colorado was one of 36 states that held an election for governor in 2018. Democrats gained seven previously Republican-held seats, and Republicans gained one previously independent-held seat. Heading into the 2018 elections, there were 16 Democratic governors, 33 Republican governors, and one independent governor. In 2018, 26 of the 33 states with a Republican governor held a gubernatorial election, while nine out of the 16 states with a Democratic governor held a gubernatorial election. Seventeen of the 36 seats up for election were open seats (four Democratic, 12 Republican, and one independent), meaning that the sitting governor was not seeking re-election.

Polls

Colorado Governor 2018, Kennedy vs. Stapleton hypothetical matchup

Colorado Governor 2018, Polis vs. Stapleton hypothetical matchup

Colorado Governor 2018, Kennedy vs. Tancredo hypothetical matchup

Colorado Governor 2018, Polis vs. Tancredo hypothetical matchup

Colorado Governor 2018, Johnston vs. Tancredo hypothetical matchup

Colorado Governor 2018, Lynne vs. Tancredo hypothetical matchup

Race ratings

The Cook Political Report, Inside Elections, and Sabato's Crystal Ball. Each race rating indicates if one party is perceived to have an advantage in the race and, if so, the degree of advantage. Race ratings are informed by a number of factors, including polling, candidate quality, and election result history in the race's district or state.

Race ratings: Colorado gubernatorial election, 2018

Election history

2014

Incumbent Gov. John Hickenlooper (D) faced three candidates in his re-election bid in 2014. Hickenlooper was challenged by Republican Bob Beauprez, Libertarian Party candidate Matthew Hess and Green Party candidate Harry Hempy. The general election took place on November 4, 2014.

Governor and Lieutenant Governor of Colorado, 2014

Party	Candidate	Vote %	Votes
	Democratic	John Hickenlooper/Joseph Garcia Incumbent	49.3%	1,006,433
	Republican	Bob Beauprez/Jill Rapella	46%	938,195
	Libertarian	Matthew Hess/Brandon Young	1.9%	39,590
	Green	Harry Hempy/Scott Olson	1.3%	27,391
	Unaffiliated	Mike Dunafon/Robin Roberts	1.2%	24,042
	Unaffiliated	Paul Fiorino/Charles Whitley	0.3%	5,923
Total Votes			2,041,574
Election results via Colorado Secretary of State

2010

On November 2, 2010, John Hickenlooper won election to the office of Governor of Colorado. He defeated Tom Tancredo (ACP), Dan Maes (R), Jaimes Brown (L), Jason Clark (I) and Paul Fiorino (I) in the general election.

Governor of Colorado, 2010

Party	Candidate	Vote %	Votes
	Democratic	John Hickenlooper	51%	912,005
	American Constitution Party	Tom Tancredo	36.5%	651,232
	Republican	Dan Maes	11.1%	199,034
	Libertarian	Jaimes Brown	0.7%	12,314
	Independent	Jason Clark	0.5%	8,576
	Independent	Paul Fiorino	0.2%	3,483
Total Votes			1,786,644
Election results via The New York Times.

2006

On November 7, 2006, Bill Ritter won election to the office of Governor of Colorado. He defeated Bob Beauprez (R), Dawn Winkler (L), Paul Fiorino (I), Clyde Harkins (C) and Charles "Chuck" Sylvester (Write-in) in the general election.

Governor of Colorado, 2006

Party	Candidate	Vote %	Votes
	Democratic	Bill Ritter	57%	888,095
	Republican	Bob Beauprez	40.2%	625,886
	Libertarian	Dawn Winkler	1.5%	23,323
	Independent	Paul Fiorino	0.7%	10,996
	Constitution	Clyde Harkins	0.6%	9,716
	Write-in	Charles "Chuck" Sylvester	0%	389
Total Votes			1,558,405
Election results via Connecticut Secretary of State.

2002

On November 5, 2002, Bill Owens won re-election to the office of Governor of Colorado. He defeated Rollie Heath (D), Ronald Forthofer (G) and Ralph Shnelvar (L) in the general election.

Governor of Colorado, 2002

Party	Candidate	Vote %	Votes
	Republican	Bill Owens Incumbent	62.6%	884,583
	Democratic	Rollie Heath	33.7%	475,373
	Green	Ronald Forthofer	2.3%	32,099
	Libertarian	Ralph Shnelvar	1.5%	20,547
Total Votes			1,412,602
Election results via Connecticut Secretary of State.

Demographics

Demographic data for Colorado

As of July 2017, Colorado had a population of approximately 5.6 million people, and its two largest cities were Denver (pop. est. 719,000) and Colorado Springs (pop. est. 484,000).