Elwell Stephen Otis (1838 - 1909) was a U.S. general who served in the Philippines late in the Spanish-American War and during the Philippine-American War.

Otis was borin in Frederick, Maryland on March 25, 1838. He served in the Union army during the Civil War. By the end of the war he was a brevet brigadier general of volunteers. He continued serving in the army during the Indian Wars. In 1893 he was appointed brigadier general in the regular army.

In May, 1898 he was appointed major general of volunteers and was sent to the Philippines with reinforcements for Wesley Merritt. When he arrived he assumed command of the VIII Corps, replacing Merritt who had became the military governor of Manila. When Merritt left, Otis was appointed Military Governor of the Philippines. He continued in command of the VIII Corps during the Battle of Manila (1899) and the first half of the Philippine-American War. He was relieved of command in 1900 and replaced with Arthur MacArthur. He returned to the United States and commanded the Department of the Lakes. He was appointed major general in the regular army in 1906.

Otis was a generally disliked commander by his subordinates and the general public. He was nicknamed "Granny" by his troops because of his age and graying hair. He died in Rochester, New York in 1909.