William Michael Cosgrove (November 26, 1916 – December 11, 1992) was an American Roman Catholic bishop.
Cosgrove was born in Canton, Ohio, and attended Saint Ignatius High School (Cleveland) and John Carroll University. He was ordained to the priesthood on December 18, 1943. On June 12, 1968, he was appointed Auxiliary Bishop of Cleveland and Titular Bishop of Trisipa by Pope Paul VI. He received his episcopal consecration on the following September 3 from Bishop Clarence George Issenmann with bishops John Francis Whealon and Harold Robert Perry as co-consecrators.
Cosgrove was named the fourth Bishop of Belleville, Illinois, on August 30, 1976. He was installed on the following October 28. After five years as bishoop, he resigned on May 19, 1981. He later died at age 76.