C16 may refer to:

• HMS C16, a 1908 British C-class submarine
• Sauber C16, a 1997 racing car
• IEC 60320 C16, an electrical connector used for electric kettles and other small appliances
• C16, the ICD-10 code for stomach cancer
• Caldwell 16 (NGC 7243), an open cluster in the constellation Lacerta
• C16 (drug), a protein kinase inhibitor used in scientific research
• C16 Close Area Suppression Weapon, the Heckler & Koch GMG's Canadian designation
• The 16th century A.D.
• Commodore 16, a home computer
• Palmitic acid, a common saturated fatty acid

C-16 may refer to:

• C-16 highway (Spain), a highway in Catalonia
• C-16: FBI, a 1997–98 American TV series
• Bill C-16, a Canadian law regarding gender expression and gender identity
• The Cessna 208 airliner, as designated in the U.S. Army
• The French Defence, as coded in the Encyclopaedia of Chess Openings
• Carbon-16 (C-16 or ¹⁶C), an isotope of carbon