GnuCash is free software for accounting environments for Mac OS X, Linux and Windows. Part of the GNU project, it is distributed under the terms of the license GNU GPL.

It is equally suited to the needs of personal accounts that of accounting for small businesses. Highly customizable, it comply with the principles of double entry bookkeeping, allows editing a chart of accounts hierarchy and includes a module for billing and customer relationship management and suppliers. The set of states needed to produce accounting results that are produced as reports that can be accompanied by charts. Adapting to the taxation arrangements in different countries is easy.

However, its interface is sometimes confusing and it does not provide protection mechanisms found in most accounting software owners. A good knowledge of accounting is necessary for production use. It can also be a very powerful teaching tool.

Originally developed for Linux, GnuCash is available for Windows since the release of version 2.2.0 on 15 July 2007.