• ACE (editor), a multi-platform collaborative editor
• ACE (file format), a data compression and archiving format
• TAO (software) (The ACE ORB), a free CORBA implementation
• Adaptive Communication Environment, an open-source cross-platform framework of object oriented classes to help the development of communication software
• Agent-Based Computational Economics, the computational study of economic processes modeled as dynamic systems of interacting agents.
• Advanced Computing Environment, a defunct computer initiative to define a "new PC" based on MIPS CPUs instead of Intel x86
• Automatic Computing Engine, a 1952 British computer
• ASCII Compatible Encoding, in the context of internationalized domain name
• ACE (software), virtualisation software from VMware
• ACE Workbench Foundation, a web portal framework in use at UBS AG

This article is about the playing card. For alternate uses of the word see Ace (disambiguation). For abbreviations with the same spelling, see ACE.

The file extension is .ace. The MIME-Type is application/x-ace-compressed.

WinAce, maintained by e-merge GmbH, is used to decompress and manipulate ACE files under Microsoft Windows. When installed, it lets the user choose between paying for a registration or installing WhenU spyware. Older versions of an extract-only program called "UNACE" were free and licensed under an open source license, but they cannot extract ACE archives from version 2.0 and newer. Besides that, there are some freeware or nagware archivers which can read the format using the official "free" UNACE-DLL, though none are free software as defined by FSF.