Super Smash Bros. for Nintendo 3DS and Wii U are two fighting video games for the Nintendo 3DS and Wii U game consoles. They were developed by Sora Ltd. and Namco Bandai Games and published by Nintendo. They act as the fourth game in the Super Smash Bros. series. The 3DS game was released on September 13, 2014. The Wii U game was released on November 21, 2014.

Like the past games in the series, Super Smash Bros. involves characters from Nintendo series fighting against each other, with the object of knocking opponents off of the stage in some way. Characters from past Super Smash Bros. games that are in these games include Mario, Luigi, Bowser, Princess Peach, Yoshi, Link, Princess Zelda, Sheik, Toon Link, Fox McCloud, Kirby, King Dedede, Pikachu, Lucario, Charizard, Donkey Kong, Diddy Kong, Samus Aran, Zero Suit Samus, Marth, Ike, Pit, Sonic the Hedgehog, and Olimar. There are six new characters: Villager from the Animal Crossing series, Mega Man from the Mega Man series, the Wii Fit Trainer, Rosalina from the Mario series., Little Mac from the Punch-Out!! series, Greninja from the Pokémon series, the Mii, Palutena from the Kid Icarus series, and Pac-Man from the Pac-Man series. There are also many hidden characters which can be unlocked. These are called "Secret Characters" by the official Super Smash Bros. Website.

The Wii U version has high-definition graphics. The Nintendo 3DS version has cel-shaded (computer graphics made to look like they were drawn by hand) graphics. Both versions have the same number of characters, but have stages that are only in either version. The Nintendo 3DS version has more stages based on Nintendo's handheld video games. The Wii U version has more stages based on their console video games. For the first time in the series, players can change the movesets of characters. They can play with characters they have changed the movesets of in single-player and with friends.