D11

D11, D.XI, D XI or D-11 may refer to:

Ships

 * ARA La Argentina (D-11), a 1981 destroyer of the Argentine navy
 * HMAS Vampire (D11), a 1956 destroyer of the Royal Australian Navy
 * HMS Impulsive (D11), a 1937 United Kingdom Royal Navy destroyer which saw service during World War II
 * Nueva Esparta, a Venezuelan Navy Nueva Esparta-class destroyer

Aircraft

 * Albatros D.XI, a 1918 German single-seat fighter biplane
 * Fokker D.XI, a 1923 Dutch single-seat fighter aircraft
 * Jodel D.11, a two-seat French commercial aircraft

Locomotives

 * Bavarian D XI, an 1895 German saturated steam locomotive model
 * GS&WR Class D11, a steam locomotive of Ireland
 * LNER Class D11, a class of British 4-4-0 locomotives introduced in 1919 by the Great Central Railway

Medicine

 * ATC code D11, Other dermatological preparations, a subgroup of the Anatomical Therapeutic Chemical Classification System
 * Warthin's tumor, ICD-10 code

Other uses

 * DXi, DirectX Instrument plugins
 * D11 motorway (Czech Republic)
 * DirecTV-11, a DirecTV satellite
 * Dublin 11, a Dublin, Ireland postal district
 * Slav Defence, 3.Nf3, Encyclopaedia of Chess Openings code
 * Colorado Springs School District 11 (D-11)
 * Caterpillar D11, a large conventional bulldozer
 * London's Metropolitan Police Specialist Firearms Command, formerly known as D11
 * HDCAM (D-11), a professional digital high definition video format