The 1970 Arizona gubernatorial election took place on November 3, 1970. Incumbent Governor Jack Williams ran for reelection to a third term as Governor. United States Ambassador to BoliviaRaúl Héctor Castro won the Democratic nomination, and narrowly lost the general election to Williams by 1.78%. Williams was sworn into his third and final term as Governor on January 5, 1971.
Due to a constitutional amendment approved by the voters in 1968, the length of the term of Governor of Arizona was changed from two years to four years, effective with the 1970 gubernatorial election. Thus, Williams became the first Arizona Governor to serve a 4-year term.