James Moriarty may refer to:
- James Moriarty (bishop) (born 1936), the Bishop Emeritus of the Roman Catholic Diocese of Kildare and Leighlin
- James F. Moriarty, United States diplomat and career foreign service officer
- James Robert Moriarty (born 1946), American lawyer noted for mass torts against major corporations
- Count Jim Moriarty, fictional character from the 1950s BBC Radio comedy The Goon Show
- Professor Moriarty, fictional character and the archenemy of the detective Sherlock Holmes