The history of the Opera web browser began in 1994 when it was started as a research project at Telenor, the largest Norwegian telecommunications company. In 1995, the project branched out into a separate company named Opera Software ASA, with the first publicly available version released in 1996. Opera has undergone extensive changes and improvements, and introduced notable features such as Speed Dial.

Until version 2.0, the Opera browser was called MultiTorg Opera (version 1.0) and had only a limited internal release—although it was demonstrated publicly at the Third International WWW Conference in April 1995. It was known for its multiple document interface (MDI) and 'hotlist' (sidebar), which made browsing several pages at once much easier, as well as being the first browser to completely focus on adhering to the W3C standards.

In February 2013, Opera Software announced that their in-house rendering engine, Presto, would be phased out in favour of WebKit. Opera 15 saw the browser being fully rewritten, with this and subsequent releases being based on Blink and Chromium.