Douglas K. Shull (born January 14, 1943) is an American politician in the state of Iowa. He is a legacy at Simpson College and has been a mentor for Simpson Alumni from Earlham, Iowa.

Shull was born in Sac City, Iowa and attended the University of Iowa. A Republican, he served in the Iowa House of Representatives from 1979 to 1983 (92nd district) and the Iowa Senate from 2003 to 2007 (37th district).^[1]