1978 Arizona House of Representatives election

The 1978 Arizona House of Representatives elections were held on November 7, 1978. Voters elected all 60 members of the Arizona House of Representatives in multi-member districts to serve a two-year term. The elections coincided with the elections for other offices, including Governor, U.S. House, and State Senate. Primary elections were held on September 12, 1978.

Prior to the elections, the Republicans held a majority of 38 seats over the Democrats' 22 seats.

Following the elections, Republicans maintained control of the chamber and expanded their majority to 42 Republicans to 18 Democrats, a net gain of four seats for Republicans.

The newly elected members served in the 34th Arizona State Legislature, during which Republican Frank Kelley was re-elected as Speaker of the Arizona House.