ATK

ATK may refer to:

Companies

 * Alliant Techsystems, an American aerospace, defense, and sporting goods company, now part of Northrop Grumman
 * ATK motorcycles, an off-road motorcycle manufacturer
 * A.T. Kearney, a management consulting firm
 * ATK Thiokol, or ATK Launch Systems Group, former names of Thiokol, an aerospace, defense and commercial products company, later part of Orbital ATK

Software

 * Accessibility Toolkit, a GNOME API for developing accessible applications
 * Andrew Toolkit, part of the Andrew Project used to create and distribute documents
 * Atomistix ToolKit, software for atomic-scale modeling

Sports

 * ATK (football club), Indian football club active from 2014 to 2020

Other uses

 * Arachidonyl trifluoromethyl ketone, an analog of arachidonic acid
 * Aboriginal traditional knowledge, cultural knowledge of aboriginal peoples
 * America's Test Kitchen, a cooking show on PBS
 * Arbetstidsförkortning, a system of additional leave entitlement in Sweden
 * Atqasuk Edward Burnell Sr. Memorial Airport, Atqasuk, Alaska (IATA Code: ATK)
 * Bruton's tyrosine kinase, a protein
 * Kiribati Grand Order (Ana Tokabeti Kiribati, post-nominals: ATK)