William H. Nicklas (1866–1960) was an Ohio architect who was best known for his church designs in partnership with Sidney Badgley.
He moved to Cleveland, Ohio in 1897 and worked in Sidney Rose Badgley's office as a draftsman.
Nicklas continued the firm for several years after the death of Badgley in 1917.
The largest portion of the firm's work was in the Cleveland area but also designed buildings throughout the Midwestern United States.
Many of these buildings are today listed on the National Register of Historic Places.