The Opera web browser originated in 1994 as a research project at Norway's Telenor, quickly spinning off into Opera Software ASA in 1995 and releasing its first public version in 1996. Initially known as MultiTorg Opera, it was distinguished by its multi-document interface, a unique 'hotlist' sidebar, and an early commitment to W3C standards.

Over the years, Opera pioneered features like Speed Dial, tabbed browsing (introduced in version 4 in 2000), mouse gestures (version 5.10 in 2001), and was an early adopter of JavaScript (version 3 in 1997) and CSS (version 3.5 in 1998). A major shift occurred in February 2013 when Opera phased out its in-house Presto rendering engine, rewriting the browser (from Opera 15) to be based on WebKit, and subsequently Blink and Chromium, marking a new era after initially moving from trialware to an ad-sponsored model with version 5 in 2000.