Winlock W. Steiwer (August 7, 1852 – July 18, 1920) was an American banker, rancher, and politician in the state of Oregon.

Born in the Willamette Valley, he made his name in Eastern Oregon as the founder of a bank and as county judge.

[1] That year he moved to Portland, Oregon, but he retained his interest in the bank he helped found.

[5] After reapportionment, he represented District 21, which comprised Sherman, Wasco, Gilliam, Grant, and Wheeler counties, in the 1903 legislature.

[6] In 1905 Steiwer was indicted for his role in the Oregon land fraud scandal along with John Hicklin Hall and Binger Hermann among others.