The 27th Arizona State Legislature, consisting of the Arizona State Senate and the Arizona House of Representatives, was constituted in Phoenix from January 1, 1965 to December 31, 1966, during Samuel Pearson Goddard Jr.'s only term as Governor of Arizona. The number of senators remained constant at two per county, totaling 28, and the members of the house of representatives also held steady at 80. The Democrats picked up two seats in the Senate, giving them a 26–2 edge in the upper house, while the Republicans gained three seats in the House, trimming the Democrats majority to 45–35.