Tim Berners-Lee created the original HTML (and associated protocols such as HTTP) on a NeXTcube workstation using the NeXTSTEP development environment. At the time, HTML was not a specification, but a collection of loosely defined elements to solve an immediate problem: the communication and dissemination of ongoing research between Berners-Lee and his colleagues. His solution later combined with the emerging international and public internet to garner worldwide attention.

 The original design of HTML was simple. The first publicly available description of HTML was a document called HTML Tags. The document describes 22 elements that made up the initial design of HTML. Thirteen of these elements still exist in HTML.

 Early versions of HTML were defined with loose syntactic rules, which helped its adoption by those unfamiliar with web publishing. Web browsers commonly made assumptions about intent and proceeded with rendering of the page. Over time, as the use of authoring tools increased, the trend in the official standards has been to create an increasingly strict language syntax. Thus the more recent versions of HTML are much stricter, demanding more precise code. Most browsers, however, continue to render pages that are far from valid HTML.

 HTML is defined in formal specifications that were developed and published throughout the 1980s, inspired by Tim Berners-Lee's prior proposals to graft hypertext capability onto a homegrown SGML-like markup language for the internet. The first published specification for a language called HTML was drafted by Berners-Lee with Dan Connolly, and was published in 1993 by the IETF as a formal "application" of SGML (with an SGML Document Type Definition defining the grammar). The IETF created an HTML Working Group in 1994 and published HTML 2.0 in 1995, but further development under the auspices of the IETF was stalled by competing interests. Since 1996, the HTML specifications have been maintained, with input from commercial software vendors, by the World Wide Web Consortium (W3C).[4] However, in 2000, HTML also became an international standard (ISO/IEC 15445:2000). The last HTML specification published by the W3C is the HTML 4.01 Recommendation, published in late 1999 and its issues and errors were last acknowledged by errata published in 2001.

 Since the publication of HTML 4.0 in late 1997, the W3C's HTML Working Group focused increasingly - and from 2002 through 2006, exclusively - on the development of XHTML, an XML-based counterpart to HTML that is described on one W3C web page as HTML's "successor". In 2007, the old HTML Working Group was renamed to XHTML2 Working Group and a new HTML Working Group was chartered to continue the development of HTML.

 XHTML is a reformulation of HTML as an XML vocabulary. XHTML can be mixed with other XML vocablaries such as SVG and MathML. XHTML served using the media type for HTML, text/html, has been embraced by many web standards advocates in preference to HTML. XHTML is routinely characterized by mass-media publications for both general and technical audiences as the newest "version" of HTML, but W3C publications, as of 2006, do not make such a claim. Neither HTML 3.2 nor HTML 4.01 have been explicitly rescinded, deprecated, or superseded by any W3C publications, and, as of 2006, they continue to be listed alongside XHTML as current Recommendations in the W3C's primary publication indices.