Peter Zack Geer (August 24, 1928 – January 5, 1997) was an American lawyer and a Democratic politician from the U.S. state of Georgia.

To win the lieutenant governorship, Geer defeated in the 1962 primary runoff his fellow segregationist and later Governor Lester Maddox, a restaurateur from Atlanta, by a margin of 55 to 45 percent.

[2] In his last act in office in January 1967, Geer presided over the legislative vote in the deadlocked gubernatorial race between Democrat Maddox and Republican U.S. Representative Howard Callaway.

Though Geer supported Maddox and ordered all legislators to vote, eleven lawmakers, including the African American Representative Julian Bond, refused to do so.

In 1973, Geer prosecuted four men accused of slaying six Alday family members in Seminole County, Georgia.