According to Wikipedia, Netcaptor was the very first browser to have tabs: https://en.wikipedia.org/wiki/Tab_(interface)#History https://en.wikipedia.org/wiki/T

According to Wikipedia, Netcaptor was the very first browser to have tabs: https://en.wikipedia.org/wiki/Tab_(interface)#History https://en.wikipedia.org/wiki/Tab_(interface)#History However, Opera supported an MDI interface before it supported tabs, and if you count that it may have supported multiple browser windows within one MDI window even earlier, which could be said to be a form of tabs. Everything depends on how you define "tabs", as usual.