Timmy is a LEGO minifig with freckles, a jaunty little blue cap, a baseball shirt, and sparkling bright eyes. He is supposed to be a boy of about seven years of age, although like all junior minifigs (including, famously, the young Anakin Skywalker fig found in Star Wars Lego), he is just as tall as all of his elders. Also, as nearly everyone who gets his hands on a Timmy has discovered firsthand, a mere change of headpiece makes Timmy into a convincing preteen girl.

Needless to say, every Adult Fan of LEGO who wants to keep his netcred alive professes hatred for Timmy on par with Trek fans' hatred for Wesley Crusher and adult Star Wars fans' loathing of Jar Jar Binks. Timmy is sometimes made into a kind of emblem for what some fans consider to be the watering down or lobotomizing of LEGO over the years. At the same time, the popularity of the Timmy of South Park is rubbing off on the Timmy of LEGO, and in some circles he shows signs of becoming a kind of cult figure (no pun intended).

Timmy first crawled out of LEGO HQ as part of the Time Cruisers theme in 1996. His actual, technical name was "Tim." Before this short-lived theme, some near-Timmys appeared in Town-themed sets. Perhaps merely because AFOLs snapped up the hodge-podge Time Cruisers sets for interesting spare parts (rather than their own dubious aesthetic merit), lots of Timmys are floating around in the LEGO hobbyist world. He now shows up in half of the LEGO web pages out there, usually as the butt of an absurd joke. Ironically, all the playerhaters have helped make Timmy the first truly famous LEGO character in history, and still the best known next to the cast of Bionicle.

Timmy now leads a double LEGO life, as a large-scale PRIMO figure in the Timmy on Tour (???) Stack n' Learn set and other large sets for infants.