The 5th Arkansas Infantry, also called the Fighting Fifth (1861–1865) was a Confederate Army infantry regiment organized in Arkansas to serve for the Confederate States of America during the American Civil War. It served throughout the war in the western theater, seeing action in the Kentucky, Tennessee and Georgia campaigns. Following its depletion in numbers the regiment was consolidated several times with other Arkansas regiments, finally merging in 1865 into the 1st Arkansas Consolidated Infantry Regiment. Another Arkansas unit also had the designation 5th Arkansas, the 5th Regiment, Arkansas State Troops which participated in the Battle of Wilson's Creek, but was never transferred to Confederate Service. There is no connection between the two units.

The 5th Regiment, Arkansas State Troops (1861) was an Arkansas State infantry regiment that served during the American Civil War. Formed in mid-1861, the regiment was assigned to the command of Brigadier General Nicholas Bartlett Pearce, commander, 1st Division, Provisional Army of Arkansas. It was disbanded after the Battle of Wilson's Creek in August 1861. Another Arkansas unit also had the designation 5th Arkansas, the 5th Arkansas Infantry Regiment which belonged to the Confederate Army of Tennessee. There is no connection between the two units.