U15

U15 or U-15 may refer to:

Submarines

• , various vessels
• , a submarine of the Austro-Hungarian Navy

University associations

• U15 (German universities), a university association in Germany
• U15 Group of Canadian Research Universities

Other uses

• U15 (Berlin U-Bahn), a transit line
• Cubohemioctahedron
• Small nucleolar RNA SNORD15
• Uppland Runic Inscription 15