A11 or A-11 can refer to:

• The A11, a road in England from London to Norwich.
• The A11 , an expressway in Switzerland.
• The A11, a German rocket design in World War II, never realized.
• The Lockheed A-11, a prototype interceptor aircraft. See Lockheed YF-12.
• A-11, an enthusiasts' name for the F-117 Nighthawk stealth fighter aircraft.
• HMS A11, an A-class submarine of the Royal Navy.