John James Joseph Monaghan (May 23, 1856 – January 7, 1935) was an American prelate of the Roman Catholic Church.

[1] He graduated from St. Charles College in Ellicott City, Maryland, in 1876, and then studied theology at St. Mary's Seminary in Baltimore.

[1] Returning to South Carolina, Monaghan was ordained to the priesthood by Bishop Patrick Neeson Lynch for the Diocese of Charleston on December 19, 1880.

[1][4] On January 26, 1897, Monaghan was appointed the third bishop of the Diocese of Wilmington by Pope Leo XIII.

[2] He received his episcopal consecration on May 9, 1987, from Cardinal James Gibbons, with Bishops Alfred Curtis and Henry Northrop serving as co-consecrators.