An element of HTML coding on a website that is used by search engines to index a website. Most meta-tags are included within the 'header' code of a website and the most important tags are the title, description and keyword tags. Rules used by different search engines govern how such tags are used, how many characters they should contain, and how they should be formatted.

There is some debate among Search Engine Optimization specialists as to just how much Meta Tags matter for SEO anymore. The "keywords" originated as a way for search engine crawlers to know what the subject matter of a web page was. It used to be the case that webmasters could "stuff" whatever keywords they wanted into this tag and see high rankings for those keywords. However, in the brave new world of the ultra-competitive internet this spamming practice no longer works. With the increase in sophistication of search engines and their crawlers web sites are now evaluated based on their actual content and popularity, not based on what they claim to be relevant to in their meta tags.

The Meta Description tag, on the other hand, is still used by some search engines - it is displayed beneath the hyperlink (<title> tag) on some Search Engine Results Pages.