The Mission Mill Museum is a complex in Salem, Oregon. It was originally the Kay Woolen Mill, which was opened in 1890 by Thomas L. Kay, from the family who founded the Pendleton Woolen Mills later on. While still in operation, the site was run by 50 employees who spent 60 hours a week on the site.

Currently, the Mission Mill Museum works as a historic museum, focusing on the mill history. In addition to the woolen mill displays, a number of historic buildings relocated from other parts of Salem, Oregon, is also exhibited on the site including the Jason Lee House, John D. Boon House, Pleasant Grove Presbyterian Church, and the Methodist Mission Parsonage.

The Mission Mill Museum is a part of the National Register of Historic Places.