Princess Daisy (Japanese: デイジー姫, Hepburn: Deijī-hime) is a character in the Mario franchise. She debuted in the 1989 Game Boy launch game Super Mario Land as the ruler of Sarasaland where she was given the role of damsel in distress for Mario to rescue. The game’s official Japanese manual described the character as "a slightly tomboyish and energetic princess", a personality that would be defined through vocal performances and unique animations in later titles. Since her appearance in Mario Tennis, she has been a staple playable character in Mario spin-off games, including Mario Party and Mario Kart. She also appears as a playable character in Super Smash Bros. Ultimate. Daisy has been primarily voiced by American voice actress Deanna Mustard from 2003 to 2022, who was succeeded by Giselle Fernandez starting with Super Mario Bros. Wonder. She is portrayed by Samantha Mathis in the live-action Super Mario Bros. film.

Princess Daisy has been a popular character for her noticeable contrast to Peach and her memorable characterization in games such as the Mario Strikers series. Though the character had largely been exclusive to spin-off titles since 2000, she was later integrated into the mainline Super Mario series of video games as a playable character in Super Mario Run and Super Mario Bros. Wonder.

Princess Daisy was created as a damsel in distress for Mario to rescue in Super Mario Land. It was produced as a launch title for the Game Boy handheld game console by Gunpei Yokoi in partnership with Satoru Okada without the input of Shigeru Miyamoto. With the aim to create a scaled-down game based on the gameplay of the 1985 Super Mario Bros., it moved away from the usual setting of the Mushroom Kingdom. The development team created Sarasaland, named after a type of floral design, and made Daisy to match that concept.

Daisy was added to Mario Tennis for the Nintendo 64 due to the developer Camelot Software Planning wanting someone whose body shape was appropriate for real-life sports. Daisy's appearance in Super Mario Bros. Wonder came about due to the game's director, Shiro Mouri, noticing that his two daughters often fought over who got to play as Princess Peach, so he wanted to resolve that and also please Mario fans. In various Mario games, she has been voiced by a variety of different individuals, including Deanna Mustard from 2003 to 2022 and Giselle Fernandez since 2023.

First appearing in 1989's Super Mario Land, Daisy is the princess of Sarasaland, a world outside of the series' usual setting of the Mushroom Kingdom, and is rescued by Mario from the alien Tatanga. In 1991, she had a smaller appearance in NES Open Tournament Golf as Luigi's caddie. In 2000, Daisy appeared as a playable character in Mario Tennis. Since then, Daisy is regularly a playable character in Mario sports games, usually wearing a sleeveless shirt and shorts in the colors of her princess gown.

In 2000, she was introduced as a playable character in the Mario Party series beginning with Mario Party 3. She is also playable in Mario Kart games, first appearing in Mario Kart: Double Dash!!, where her course is known as Daisy Cruiser. Mario Kart Wii also added Baby Daisy, her toddler version, which has since appeared in multiple games. Other playable appearances have included Super Mario Run, Fortune Street,^{[citation needed]} and Super Mario Bros. Wonder. She was added to Super Smash Bros. Ultimate as a playable character, after previously appearing as a trophy. Her gameplay in Ultimate is largely identical to that of Princess Peach.

Daisy appears as a skin in multiple video games, including Super Mario Maker and Minecraft. Daisy's Amiibo figurine for the Super Mario franchise was released on November 4, 2016, to coincide with the release of Mario Party: Star Rush. Meanwhile, her Amiibo figurine related to the Super Smash Bros. franchise was released on February 13, 2019. Daisy was added to Dr. Mario World in a post-launch update in 2019. In 2022, she was also added as a post-launch downloadable character to Mario Strikers: Battle League.

Daisy is one of the main characters of 1993's Super Mario Bros. film, loosely based on the games, portrayed by Samantha Mathis. She is a student of archaeology at New York University with whom Luigi falls in love. Daisy is kidnapped by two henchmen of President Koopa, the dictator of Dinohattan, who wants to merge his world and the human world, necessitating Mario and Luigi to save her.