Samurai Jack is an American animated science fantasy action-adventure television series created by Genndy Tartakovsky for Cartoon Network and later its nighttime programming block Adult Swim. It was produced by Cartoon Network Studios. Tartakovsky conceived Samurai Jack after finishing his work on his first Cartoon Network original series, Dexter's Laboratory, which premiered in 1996. Samurai Jack took inspiration from the 1972 televised drama Kung Fu, starring David Carradine, as well as Tartakovsky's fascination with samurai culture and the Frank Miller comic series Ronin.

The titular character is an unnamed Japanese samurai prince who wields a mystic katana capable of cutting through virtually anything. He sets out to free his kingdom after it is taken over by an evil, shapeshifting demon lord known as Aku. The two engage in a fierce battle, but just as the prince is about to deal the final strike, Aku sends him forward in time to a dystopian future ruled by the tyrannical demon. Adopting the name "Jack" after being addressed as such by beings in this time period, he quests to travel back to his own time and defeat Aku before he can take over the world. Jack's search for a way back to his own time period transcends Aku's control, but Jack's efforts are largely in vain due to the way back to his home ending up just out of his reach.

The series was initially broadcast from August 10, 2001, to September 25, 2004, airing for four seasons comprising thirteen episodes each, without concluding its overarching story. The show was revived thirteen years later with a darker, more mature fifth season that provided a conclusion to the series, with Williams Street assisting in production; the fifth season premiered on Cartoon Network's Adult Swim as part of its Toonami programming block on March 11, 2017, and concluded with its final episode on May 20, 2017. Episodes were directed by Tartakovsky, often in collaboration with others.

Samurai Jack received critical acclaim and won eight Primetime Emmy Awards, including Outstanding Animated Program, as well as six Annie Awards and an OIAF Award. It is widely considered to be one of the greatest animated series of all time.

"Long ago in a distant land, I, Aku, the shapeshifting master of darkness, unleashed an unspeakable evil, but a foolish samurai warrior wielding a magic sword stepped forth to oppose me. Before the final blow was struck, I tore open a portal in time and flung him into the future where my evil is law. Now the fool seeks to return to the past and undo the future that is Aku!"

Samurai Jack tells the story of an unnamed young prince from a kingdom set in feudal Japan, whose father, the emperor of Japan, was given a magical katana from a trinity of gods—Ra, Rama and Odin—that he could and had used to defeat and imprison the supernatural shapeshifting demon Aku. Eight years later Aku was freed, took over the land and held the Emperor hostage, but not before the prince was sent away by his mother to travel so that he could train around the world and return with the magic sword to defeat Aku. On his return, the prince-turned-samurai faced and almost vanquished Aku, but before he could deliver the final blow, the demon exiles him to the distant future, anticipating that he would be able to deal with the samurai by that time.

The era in which the samurai arrives is a retrofuturistic dystopia where Aku reigns supreme. The first people the samurai encounters call him "Jack" as a form of slang, which he adopts as his name; his given name is never revealed. Jack only has his kimono, geta and sword to his avail in his adventures. Most episodes depict Jack overcoming various obstacles in his quest to travel back to his own time and vanquish Aku; his quest is prolonged occasionally by moments where either he nearly succeeds in returning to his own time, or conversely, Aku nearly succeeds in defeating Jack, only to be undermined by the unexpected.

Besides humans, the retro-futuristic world of the future is inhabited by a variety of denizens, such as robots, extraterrestrials, anthropomorphic animals, monsters, magical beings and deities. Some areas may have advanced technologies like flying cars, while others resemble ancient times or are in industrial conditions. Moreover, Aku has brought aliens from other planets to inhabit Earth, after destroying the habitability of their home worlds. Criminals and fugitives of all kinds are very common on his Earth, including bounty hunters who voluntarily hunt for Jack in exchange for a cash reward. Mythological and supernatural creatures make regular appearances and coexist among the technologically advanced inhabitants.