1964 Arizona Senate election

The 1964 Arizona Senate election was held on November 3, 1964. Voters elected all 28 members of the Arizona Senate to serve two-year terms. At the time, each of Arizona's 14 counties elected two state senators for a total of 28 members of the Arizona Senate. Primary elections were held on September 8, 1964.

Prior to the elections, the Democrats held a supermajority of 24 seats over the 4 Republican seats.

Following the election, Democrats maintained control of the chamber and increased their supermajority to 26 Democrats to 2 Republicans. The newly elected senators served in the 27th Arizona State Legislature, which met for two regular sessions at the State Capitol in Phoenix. The first opened on January 11, 1965, and adjourned on April 20; while the second convened on January 10, 1966, and adjourned on April 23. There were four Special Sessions, all in 1965. The first Special Session convened April 21, 1965, and adjourned sine die on May 10; the second convened on May 11, 1965, and adjourned sine die on June 15;  the Third Special session convened on June 16, 1965, and adjourned sine die on July 1;  with the final Special Session, the fourth, convened September 13, 1965, and adjourned sine die on October 9.

The Democrats had a net gain of 2 seats in the Arizona Senate following the election.