An election was held on November 6, 2018, to elect all 100 members to Montana's House of Representatives. The election coincided with the elections for other offices, including the U.S Senate, U.S. House of Representatives, and state senate. The primary election was held on June 5, 2018.

Incumbent Republican Steve Gunderson had represented the 1st district since 2017.

Incumbent Republican Mike Cuffe had represented the 2nd district since 2011. Cuffe was term-limited and successfully ran for a seat in the Montana Senate.

Incumbent Democrat Zac Perry had represented the 3rd district since 2015.

Incumbent Republican Matt Regier had represented the 4th district since 2017.

Incumbent Democrat Dave Fern had represented the 5th district since 2017.

Incumbent Republican Carl Glimm had represented the 6th district since 2013.

Incumbent Republican Frank Garner had represented the 7th district since 2015.