XSL is a family of recommendations for defining XML document transformation and presentation. It consists of three parts:

XSL Transformations (XSLT)

a language for transforming XML;

The XML Path Language (XPath)

an expression language used by XSLT (and many other languages) to access or refer to parts of an XML document;

XSL Formatting Objects (XSL-FO)

an XML vocabulary for specifying formatting semantics.

An XSLT stylesheet specifies the presentation of a class of XML documents by describing how an instance of the class is transformed into an XML document that uses a formatting vocabulary, such as (X)HTML or XSL-FO. For a more detailed explanation of how XSL works, see the What Is XSL page.

XSLT is developed by the W3C XSLT Working Group (members only) whose charter is to develop the next version of XSLT. XSLT is part of W3C's XML Activity, whose work is described in the XML Activity Statement.

XPath is developed jointly by the XQuery and XSLT Working Groups.

The XSL-FO work at W3C was taken over by the XML Print and Page Layout Working Group which has now been closed.