U15

U15 or U-15 may refer to:

Submarines

 * GERMAN SUBMARINE U-15, various vessels
 * GREEK SUBMARINE Argonaftis
 * SM U-15, a submarine of the Austro-Hungarian Navy

Other uses

 * U15 (Berlin U-Bahn), a transit line
 * U15 (German universities), a university association in Germany
 * Cubohemioctahedron
 * Small nucleolar RNA SNORD15
 * U15 Group of Canadian Research Universities
 * Uppland Runic Inscription 15