Dexter's Laboratory is an American animated television series created by Genndy Tartakovsky for Cartoon Network as the first Cartoon Cartoon. The series follows Dexter, an enthusiastic boy-genius with a hidden science laboratory in his room full of inventions, which he keeps secret from his unsuspecting parents, who are only referred to as Mom and Dad. Dexter is at constant odds with his older and more extraverted sister Dee Dee, who always gains access to the laboratory and inadvertently foils his experiments. Dexter has a bitter rivalry with his neighbor and classmate Mandark, a nefarious boy-genius who attempts to undermine Dexter at every opportunity. Prominently featured in the first and second seasons are other segments focusing on superhero-based characters Monkey, Dexter's pet lab-monkey/superhero, and the Justice Friends, a trio of superheroes who share an apartment.

Tartakovsky pitched the series to Fred Seibert's first animated shorts showcase What a Cartoon! at Hanna-Barbera, basing it on student films he produced at the California Institute of the Arts. Four pilots aired on Cartoon Network and TNT from 1995 to 1996. Viewer approval ratings led to a half-hour series, which consisted of two seasons totaling 52 episodes, airing from April 27, 1996, to June 15, 1998. On December 10, 1999, a television film titled Dexter's Laboratory: Ego Trip aired as the intended series finale, and Tartakovsky left to begin working on Samurai Jack.

In November 2000, the series was renewed for two seasons containing 26 total episodes, which began airing on November 18, 2001, and concluded on November 20, 2003. Due to Tartakovsky's departure, the series was retooled in the last two seasons under Chris Savino as showrunner and a new production team at Cartoon Network Studios.

Dexter's Laboratory, particularly its first two original seasons, received critical acclaim and became one of Cartoon Network's most successful original series. It won three Annie Awards, with nominations for four Primetime Emmy Awards, four Golden Reel Awards, and nine other Annie Awards. The series is notable for helping launch the careers of animators Craig McCracken, Seth MacFarlane, Butch Hartman, Paul Rudish, and Rob Renzetti. Spin-off media include children's books, comic books, DVD and VHS releases, music albums, toys, and video games.