The 51st Arizona State Legislature, consisting of the Arizona State Senate and the Arizona House of Representatives, was constituted in Phoenix from January 1, 2013, to December 31, 2014, during the last two years of Jan Brewer's first full term in office.

The Democrats gained five seats in the Senate, decreasing the Republican majority to 16–14.

The Democrats also gained four seats in the lower chamber, leaving the Republicans with a 36–24 majority.

The Legislature met for two regular sessions at the State Capitol in Phoenix.

The first opened on January 14, 2013, and adjourned on June 14, while the Second Regular Session convened on January 13, 2014, and adjourned sine die on April 24.