On November 6, 2018, a general election in the U.S. state of Missouri was held for the post of State Auditor of Missouri. The election for Missouri State Auditor coincided with the U.S. federal midterm elections that were held throughout all 50 states, as well with other state legislative and local races in Missouri. Missouri's Class 1 United States Senate seat was also up for election on November 6, 2018.
The primary elections for this race were held on August 7, 2018. The Democrats nominated incumbent Missouri State Auditor Nicole Galloway, while the Republicans nominated attorney Saundra McDowell.
Galloway won election to a full term. Prior to this, Galloway had been appointed to the post by former Governor Jay Nixon in 2015, following the death of Tom Schweich.
Following the Republican victories in the elections on November 8, 2016, for Governor of Missouri, U.S. Senate, Lieutenant Governor, Missouri State Treasurer, Attorney General, and Secretary of State, Galloway and U.S. Senator Claire McCaskill became the only two remaining Democratic statewide officeholders in Missouri. McCaskill's failed re-election campaign in 2018 made Galloway the state's only Democratic statewide officeholder and only female statewide elected official. Her victory also marks the only Democratic win in a statewide election in the state since 2012. As of 2025, this was the last time a Democrat won a statewide election in Missouri.
Democratic primary.
Results.
! scope="col" colspan="2" style="width: 15em" |Party
! scope="col" style="width: 17em" |Candidate
! scope="col" style="width: 5em" |Votes
! scope="col" style="width: 3.5em" |%
! colspan="3" style="text-align:right;" | Total votes
Republican primary.
Results.
! scope="col" colspan="2" style="width: 15em" |Party
! scope="col" style="width: 17em" |Candidate
! scope="col" style="width: 5em" |Votes
! scope="col" style="width: 3.5em" |%
! colspan="3" style="text-align:right;" | Total votes
General election.
Polling.
! Poll source
! Date(s)administered
! Samplesize
! Marginof error
! style="width:100px;"| NicoleGalloway (D)
! style="width:100px;"| SaundraMcDowell (R)
! Other
! Undecided
Results.
! scope="col" colspan="2" style="width: 130px"|Party
! scope="col" style="width: 17em"|Candidate
! scope="col" style="width: 5em"|Votes
! scope="col" style="width: 3.5em"|%
! scope="col" style="width: 3.5em"| ;templatestyles src="Template:Tooltip/styles.css" / ;±%
! colspan="3" style="text-align:right;" | Total votes
Notes.
Partisan clients
References.
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