Walter Jeremiah Maddock (September 13, 1880 – January 25, 1951) was an American politician in North Dakota, US.

He served the remainder of Sorlie's term and sought re-election, but he failed to win the race against George F. Shafer.

After being defeated in the election, Maddock returned to farming and was active in organizing farmers' cooperatives.

From 1937 until his retirement in 1950, he served as the head of North Dakota's Farm Security Administration office.

Maddock died on January 25, 1951, and is buried in Saint Mary's Cemetery, Bismarck, Burleigh County, North Dakota, US.