Joseph Hill "Joss" Whedon is an American screenwriter, director, producer, comic book writer, and composer. He is best known as the creator of several television series, including the supernatural drama Buffy the Vampire Slayer (1997–2003) and its spinoff Angel (1999–2004), the short-lived space Western Firefly (2002), the Internet musical miniseries Dr. Horrible's Sing-Along Blog (2008), the science fiction drama Dollhouse (2009–2010), the Marvel Cinematic Universe film The Avengers (2012) and series Agents of S.H.I.E.L.D. (2013–2020), and the science fiction drama The Nevers (2021).

After beginning his career in sitcoms, Whedon wrote the horror comedy film Buffy the Vampire Slayer (1992) – which he later adapted into the acclaimed television series of the same name – co-wrote the Pixar animated film Toy Story (1995), and wrote the science fiction horror film Alien Resurrection (1997). After achieving success as a television showrunner, Whedon returned to film to write and direct the Firefly film continuation Serenity (2005), co-write and produce the horror comedy film The Cabin in the Woods (2012), and write and direct the Shakespeare adaptation Much Ado About Nothing (2012).

For the Marvel Cinematic Universe, Whedon wrote and directed the ensemble superhero film The Avengers (2012) and its sequel Avengers: Age of Ultron (2015). He also co-wrote the DC Extended Universe superhero film Justice League (2017), for which he also served as director for re-shoots, replacing Zack Snyder.

Whedon has also worked as a composer and comic book writer, both for comic book continuations of television series he created and for established franchises, such as Astonishing X-Men. He is the founder of Mutant Enemy Productions and co-creator of Bellwether Pictures.

Beginning in July 2020, multiple actors, producers, and writers spoke out against Whedon following the toxic workplace environment he had allegedly created in many of his projects. Whedon has denied any wrongdoing, while acknowledging that he can be "confrontational."