Walter Downey Guilbert (February 11, 1844 – February 15, 1911) was a Republican politician in the U.S. State of Ohio who was Ohio State Auditor 1896–1909. Guilbert was born at Guernsey County, Ohio. He studied in local schools, and at an academy in Wenona, Illinois. After leaving school, he remained in the Midwest until 1869. He then returned to Ohio and manufactured staves and engaged in salt making at South Olive, Noble County until 1881.