Fifth Man may refer to:

• "The Fifth Man", an episode of Stargate SG-1
• The Fifth Man (novel), a novel by John B. Olson and Randall S. Ingermanson
• the unknown member of the Cambridge Five (aka the Cambridge Four), a ring of Soviet spies

• Crumhorn Lake
• Crumhorn Mountain
• Crumley, James
• Crumley-Lynn-Lodge House
• Crumlin (Monmouthshire) railway station
• Crumlin railway station, Northern Ireland
• Crumlin Viaduct (Northern Ireland)
• Crum Lynne (SEPTA station)
• Crum Lynne station (Pennsylvania)
• Crum Lynne station (SEPTA)
• Crum Lynne station (SEPTA Regional Rail)
• Crum, Maurice
• Crummell
• Crummell, Alexander
• Crummey, Andrew
• Crummey, Michael
• Crumm, William
• Crummy
• Crummy, Andrew
• Crummy (disambiguation)
• Crummy Stuff
• Crumomyia
• Crumomyia fimetaria
• Crumomyia nitida
• Crumomyia roserii