Ralph Henry Van Deman (September 3, 1865 – January 22, 1952) was a United States Army officer, sometimes described as "the father of American military intelligence.

Van Deman then entered the Army as a surgeon, before attending the Infantry and Cavalry School at Fort Leavenworth in early 1895.

After two years he was promoted to captain and was moved to the Bureau of Insurgent Records in Manila, which he helped transform into the Philippine Military Information Division.

After graduation in 1906, he and Captain Alexander Coxe were sent on a covert mission to China to reconnoiter and map lines of communication around Peking.

He was convinced that the Army must have a coordinated intelligence organization if it were to avoid defeat in the near future, especially as it was now obvious that the U.S. would soon be involved in the war in Europe.

Short of manpower, Van Deman relied on private groups which he organized into the American Protective League.

In 1918 Van Deman went to France to work for Colonel Dennis Nolan, G2 of the AEF, handing over control of the MID to Brigadier-General Marlborough Churchill.

After overseeing security at the Paris Peace Commission, he returned to Washington in August 1919 to briefly serve as Deputy Chief of the MID.

After retiring he used the contacts he had established during World War I in the American Protective League to privately compile files on suspected subversives and foreign agents.

Notable among his recommendations was that he sent a passionate defense of Japanese-American citizens to President Roosevelt;[6] the advice that they were not a threat was, however, ignored (leading to the Japanese American internment).

Van Deman Street, located within the former Fort Holabird in Baltimore, MD; is named after him in honor of his service in Military Intelligence.