Dance Dance Revolution 3rdMix, or 3rdMix, is the 3rd game in the Dance Dance Revolution series of music video games. It was released in the arcades by Konami on October 30, 1999. Although only officially released in Japan, units exist worldwide. It has a total of 68 songs, 35 of which were new to Dance Dance Revolution.

The core gameplay of 3rdMix is the same as the previous Dance Dance Revolution games. 3rdMix featured a brand new scoring system, instead of being heavily combo-based like the last two mixes, combos are of virtually no importance. The maximum score for each song is 10,000,000 (all Perfects). Perfects are worth twice as many points as Greats, and steps toward the end are worth progressively higher points than steps toward the beginning. In nonstop mode, a 2x, 3x and 4x multiplier apply to the 2nd, 3rd and 4th songs respectively, making a perfect nonstop worth 100,000,000 points.

3rdMix was also the first version of DDR where different beats (compared to a 4-beat register) alternate different colors, making 1/4, 1/8, 1/12 and 1/16 steps look different and making it easier for the player to recognize changing rhythms. This color scheme is called "vivid" mode, whereby the old scheme of all arrows being the same color is henceforth referred to as "flat" mode. Flat appears as an option and modifier in later versions of DDR.

This release marked the first time lyrics were displayed during gameplay for every song. This can be turned on or off by the arcade operator. This feature was later dropped from future arcade mixes, although some home versions contain this as an option, and most European Dancing Stage versions contain this on by default.

3rdMix also allowed to choose characters, and while their purpose is for the most part aesthetical, the chosen character affects which beatmania remix song can be played at one playthorugh.