Warren Heywood Williams (1844 in New York City – January 1888) was an American architect, who spent most of his career working in the U.S. state of Oregon. Starting in 1860, he apprenticed in San Francisco as a draftsman at the architectural firm of his father, Stephen H. Williams, and Henry W. Cleaveland. Warren Heywood Williams and his wife, Christina (c. 1847–1929), had two sons who became architects, Warren Franklin Williams (died 1917) and David Lochead Williams (born September 2, 1866). Williams died of pneumonia in January 1888.