C99 is a past version of the C programming language standard.
C99 or C-99 may also refer to:
Science and technology C99, a C compiler for the TI-99/4A home computer C99, a fragment of the amyloid precursor protein created by beta-secretase C99Shell, also known as C99, is a malicious web shell
Other uses C99, a model of Beechcraft Model 99 aircraft Convair C-99, a military aircraft Ruy Lopez (ECO code), a chess opening Minimum Wage Fixing Machinery (Agriculture) Convention, 1951 (ILO code) C99, is also known as Coalsack Nebula
See also HMS Blake (C99), a 1945 British Royal Navy cruiser
es:C (lenguaje de programación)#C99 it:C (linguaggio)#C99