Groot (/ɡruːt/) is a character appearing in American comic books published by Marvel Comics. Created by Stan Lee, Larry Lieber and Jack Kirby, the character first appeared in Tales to Astonish #13 (November 1960). An extraterrestrial, sentient tree-like creature, the original Groot first appeared as an invader that intended to capture humans for experimentation. The character can only say the repeated line "I am Groot", but has different meaning. In the Marvel Cinematic Universe, Star-Lord, Thor, and Rocket Raccoon are able to understand him.

The character was reintroduced as a heroic, noble being in 2006, and appeared in the crossover comic book storyline "Annihilation: Conquest." Groot went on to star in its spin-off series, Guardians of the Galaxy, joining the team of the same name.

Groot has been featured in a variety of associated Marvel merchandise, including animated television series, toys and trading cards. Vin Diesel voices Groot (with Krystian Godlewski playing the character via performance capture) in the Marvel Cinematic Universe (MCU) film Guardians of the Galaxy (2014) and cameoed as Groot's son (also named Groot) (with James Gunn playing the character via performance capture for dancing), colloquially known as "Baby Groot". Diesel reprised the role in the MCU films Guardians of the Galaxy Vol. 2 (2017), Avengers: Infinity War (2018), Avengers: Endgame (2019), Thor: Love and Thunder (2022) and The Guardians of the Galaxy Holiday Special. He portrayed Baby Groot in the short form series I Am Groot, and the upcoming Guardians of the Galaxy Vol. 3 (2023). Fred Tatasciore voices Groot on the Disney California Adventure ride Guardians of the Galaxy: Mission Breakout and Diesel voiced Groot as a cameo in the film Ralph Breaks the Internet (2018).