U16 may refer to:
Naval vessels
- , various vessels
- , a Black Swan-class sloop of the Royal Navy
- , a Grimsby-class sloop of the Royal Navy
- , a submarine of the Austro-Hungarian Navy
Other uses
- Bugatti U-16, an automobile engine
- Cubitruncated cuboctahedron
- Small nucleolar RNA SNORD16
- Uint16_t, a 16-bit unsigned integer
- Uppland Runic Inscription 16
- U16, or under-16, is a youth sports category.