横幅式广告又称旗帜广告，通常横向出现在网页中，最常见的尺寸是468×60和468×80，目前还有728x90大尺寸型。是网络广告比较早出现的一种广告形式。以往以jpg或者gif格式为主，伴随互联网的发展，swf格式的旗帜广告也比较常见了。

A web banner or banner ad is a form of advertising on the World Wide Web delivered by an ad server. This form of online advertising entails embedding an advertisement into a web page. It is intended to attract traffic to a website by linking to the website of the advertiser. In many cases, banners are delivered by a central ad server.