Sub may refer to:
Common abbreviations of words beginning with "sub-"
Bottom (BDSM), or "sub" for "submissive"
Sub (TV channel)
SUB, subtraction processor command
SUB, substitute character, ASCII character 26
.sub (disambiguation), several file extensions
<sub>, an HTML tag for subscript
SUB designates a subroutine in some programming languages
Subscript and superscript
Seafarers' Union of Burma
Juanda International Airport, Surabaya, Indonesia, IATA code