William Rock Painter (August 27, 1863 – July 1, 1947) was an American politician.

In 1894 Painter left the engineering field to become editor and publisher of the Daily and Weekly Democrat, newspaper in Carroll County.

Painter died in July 1947 and is buried in Oak Hill Cemetery, Carrollton, Missouri.

Soon after leaving office, he was appointed as chairman of the (Missouri) Prison Board in 1917.

Painter finished his political career as state Senator from the Missouri 8th District, a position he held until 1930.