U11
U11 may refer to:

Naval vessels 
 
 , various vessels
 , a sloop of the Royal Navy
 , a submarine of the Austro-Hungarian Navy

Other uses 
 U11 (Berlin U-Bahn), a planned transit line
 U11 (Nuremberg U-Bahn), a discontinued transit line
 BMW X1 (U11), a German crossover
 HTC U11, a smartphone
 Nissan Bluebird (U11), a Japanese sedan
 Truncated cuboctahedron
 U11 spliceosomal RNA
 Udet U 11 Kondor, a German prototype airliner
 Uppland Runic Inscription 11