T21

T21 may refer to:

Aircraft

 * Junkers T.21, a German reconnaissance aircraft produced in the Soviet Union
 * Slingsby T.21, a British training glider

Rail and transit

 * Minami-morimachi Station, in Kita-ku, Osaka, Japan
 * Myōden Station, in Ichikawa, Chiba, Japan
 * SJ T21, a Swedish locomotive
 * Yakuriguchi Station, in Takamatsu, Kagawa Prefecture, Japan

Ships and boats

 * ARV Amazonas, a tank landing ship of the Venezuelan Navy
 * GERMAN TORPEDO BOAT T21
 * Mistral T-21, a Canadian sailboat

Other uses

 * T21 (rocket), an American chemical warfare rocket
 * Down syndrome, or trisomy 21
 * Estonian national road 21
 * T21 road (Tanzania)
 * T21 Light Tank, an American light tank
 * ThinkPad T21, a notebook computer
 * Trisomie 21, a French cold wave group