Above Poverty Line, the section of people who can fulfil their minimum basic needs

Ascension Parish Library, a parish library system in Louisiana

APL, United States Navy hull classification symbol for Barracks Craft

Australian Premier League, an online football gaming league

apl, file extension of the Monkey's Audio metadata file

Acute promyelocytic leukemia, a subtype of acute myelogenous leukemia

APL (programming language), a computer programming language with specialized array processing capabilities

Applied Physics Laboratory, Johns Hopkins University

AMD Performance Library, a compiler library for AMD multi-threaded processors

American Protective League, a WWI era pro-war organization

American President Lines, a Singapore-based container transportation and shipping company

Applied Physics Letters, journal published by American Institute of Physics

Furthermore, APL is the name of an asteroid: 132524 APL

Association of Pension Lawyers

Adaptive Public License

Nampula Airport, Mozambique, from its IATA airport code

apl.de.ap, pseudonym of Allan Pineda Lindo, a member of hip hop group The Black Eyed Peas

AROS Public License, license of AROS Research Operating System, formerly Amiga Research Operating System