Ernest John Primeau (September 17, 1909 – June 6, 1989) was an American prelate of the Roman Catholic Church. He served as Bishop of Manchester from 1960 to 1974.
Primeau was born in Chicago, Illinois, and there studied at Archbishop Quigley Preparatory Seminary. He was ordained to the priesthood by Cardinal George Mundelein on April 7, 1934. After serving at parishes and schools in the Archdiocese of Chicago, he spent twelve years in Rome, and was rector of Mundelein Seminary, Chicago's Archdiocesan seminary. In 1958 he was named pastor of Our Lady of Mount Carmel Church in Chicago.
On November 27, 1959, Primeau was appointed the sixth Bishop of Manchester, New Hampshire, by Pope John XXIII.
He received his episcopal consecration on February 13, 1960 from Cardinal Albert Gregory Meyer, with Bishops Martin Dewey McNamara and Raymond Peter Hillinger serving as co-consecrators. He was installed at Cathedral of St. Joseph on March 15, 1960. During the Second Vatican Council (1962-1965), Primeau was one of the more influential and articulate voices among the Council Fathers. He spoke out in support of the empowerment of the laity, once declaring, "Let this talk of their duty of subjection cease." He also founded the first foreign mission of the diocese in 1963 in Cartago, Colombia. During Primeau's tenure, the number of Catholics increased by 43,000 and the number of parishes by 11; however, weekly Mass attendance declined from over 70% to below 50%.
After thirteen years as bishop, he retired on January 30, 1974 at the age of 65. He had often advocated that bishops should retire at that age and so he became the first Bishop of Manchester to resign from office. Primeau died in 1989 at age 79.