Tab Mix Plus is a Mozilla Firefox extension that adds to the tabbed browsing functions in Firefox. It remains regularly updated as of 2025 and is compatible with Waterfox and some other forks. It was a popular extension on Mozilla Add-ons, which records download statistics. TMP is a collection of features from other extensions built in one package. Lifehacker named it one of their "Top 10 must-have Firefox extensions" for 2009. PC World said that "With Tab Mix Plus, Firefox tabs go past the obvious and into the indispensable... it's hard to imagine how you lived without it." As the only extension providing multi-row tab support, Wired and CNET both called it a "must-have" that is "powerful" and "gives you what feels like an infinite amount of control over tab behaviour."