A11, A 11 or A-11 may refer to:

Military

• Aero A.11, a Czechoslovakian bomber produced before World War II
• Consolidated A-11, an attack version of the Consolidated P-30 fighter plane of the 1930s
• HMS A11, an A-class submarine of the Royal Navy
• Matilda Mk I, a British Army infantry tank
• Aggregate 11, a proposed military rocket of Nazi Germany
• A-11 Ghibli, the Italian designation for the AMX International AMX

Roads

• A11 road, in several countries

Other uses

• Apollo 11
• A-11 offense, an American Football shotgun formation involving 2 quarterbacks and 9 other potentially eligible receivers
• Arrows A11, a 1989 British racing car
• ATC code A11 Vitamins, a subgroup of the Anatomical Therapeutic Chemical Classification System
• British NVC community A11 (Potamogeton pectinatus - Myriophyllum spicatum community), a British Isles plant community
• Chery A11, a 1999 Chinese car
• HLA-A11, an HLA-A serotype
• American Airlines Flight 11, a plane that was hijacked and crashed into the World Trade Center in the September 11 attacks
• English Opening, Encyclopaedia of Chess Openings code
• Apple A11, an ARM SoC mobile processor designed by Apple.
• "A-11", a 1963 country song written by Hank Cochran