Opera 4 is a web browser developed by Opera Software ASA, available for download in full install version for Windows platforms from legacy sources. This version of Opera was officially released on 2000-06-28 for public access and a brief summary of important updates and change log pertaining to this edition can be read below.

Opera 4 was released with code name of Elektra and has been proud to be announced as the fastest browser available now in the world. With this edition Opera becomes the third browser in the internet world following Internet Explorer and Netscape Navigator.

Opera 4 has an inbuilt Email client and news client and support a huge list of protocols and W3C Compliance norms including TLS 1.0, SSL 3.0, CSS 1 & 2, XML, HTML 4.0 and Sun Micro Systems' Free Java Plug-in version 1.3.