William Elting Johnson (October 17, 1837 – December 16, 1912) was an American physician and politician from New York.

He graduated from Albany Medical College in 1859, and practiced medicine in Waverly.

During the American Civil War he was an army surgeon from 1862 to 1865 with the 109th New York Volunteers.

On May 1, 1873, he married Mattie Maria Fuller (1847–1914), and they had one daughter.

Johnson was a presidential elector in 1888, voting for Benjamin Harrison and Levi P. Morton; and a member of the New York State Senate (38th D.) from 1896 to 1900, sitting in the 119th, 120th, 121st, 122nd and 123rd New York State Legislatures.