Paper Mario is a video game series and part of the Mario franchise, developed by Intelligent Systems and published by Nintendo. It combines elements from the role-playing, action-adventure, and puzzle genres. Players control a paper cutout version of Mario, usually with allies, on a quest to defeat the antagonist. The series consists of six games and one spin-off; the first, Paper Mario (2000), was released for the Nintendo 64, and the most recent, a 2024 remake of 2004's Paper Mario: The Thousand-Year Door, for the Nintendo Switch.

The original Paper Mario began as a sequel to Super Mario RPG (1996), developed by Square for the Super Nintendo Entertainment System. Changes in development resulted in the game becoming a standalone game titled Mario Story in Japan. Although the early games in the series were well-received, Kensuke Tanabe wanted each one to have different genre and core gameplay elements. This led the series to slowly move genres from role-playing to action-adventure, though some role-playing elements are still present later in the series.

The first two games in the series, Paper Mario and The Thousand-Year Door, received critical acclaim, and were praised for their story, characters, and unique gameplay. When Paper Mario: Sticker Star was released in 2012, the series began to receive many complaints about its change in genre, removal of original fictional races, and less unique character designs, but continued to garner praise for its writing, characters, music, and enhanced paper-inspired visuals. Super Paper Mario is the best-selling game in the series, with 4.3 million sales as of 2019. The series has collectively sold 12.54 million copies.

Several Paper Mario games were nominated for at least one award; The Thousand-Year Door won "Role Playing Game of the Year" at the 2005 Interactive Achievement Awards, Super Paper Mario won "Outstanding Role Playing Game" at the 12th Satellite Awards in 2007, and Sticker Star won "Handheld Game of the Year" at the 16th Annual D.I.C.E. Awards in 2012. The Origami King was nominated for three, the most at once for the series. The games, mainly the first two titles, have inspired various indie games including Bug Fables: The Everlasting Sapling. Numerous Paper Mario elements have also been included in the Super Smash Bros. series.

In the series, Mario is tasked with a quest to explore either the Mushroom Kingdom or a similar world. Each game divides the world into several explorable areas that contain puzzles and interactive elements, such as obstacles that Mario has to hit with his hammer, that need to be completed to progress in the story. The locations are designed to look as if they are made out of paper, and contain coins and other collectibles, such as hidden trophies. There are also non-player characters (NPCs) which Mario can talk to. All games except Super Paper Mario feature a turn-based combat system, where Mario and one or more opponents take turns attacking one another.

The first two games, Paper Mario and Paper Mario: The Thousand-Year Door, feature elements similar to that of a typical role-playing video game (RPG). Mario encounters multiple allies that join him on his journey, who can help complete tasks in the worlds and fight in combat, the latter of which is similar to other RPG games. The player can either perform a regular attack, where they time a button-press on the controller to deal more damage, or use a special attack, which is more powerful but consumes flower points (FP)—an in-game statistic—when used. When defeating an enemy, experience points (known in-game as Star Points, or SP) are awarded, which makes Mario and his allies more powerful as they progress. Upgrades to special attacks can be found in the overworlds.

Super Paper Mario, the third game in the series, deviates from the RPG genre and plays more as a platform game instead. Unlike the previous two games, which use a turn-based combat system, Mario does not enter a combat phase and instead fights the enemy in the overworld in real-time. XP is still awarded for defeating enemies. Although Mario does not fight alongside unique partners, Luigi, Princess Peach, and Bowser are playable and a part of Mario's party. In addition, allies known as Pixls, which grant abilities for combat and traversing levels, can be summoned and used.

Since Paper Mario: Sticker Star, the Paper Mario games were aimed more towards the action-adventure genre. RPG elements, such as experience points, allies, a complex plot and variety of fictional races, were reduced. It instead emphasized puzzle-solving, a new experience point system, and new strategic and somewhat puzzle-like gameplay around combat.