Megatokyo (メガトーキョー) is an English-language webcomic created by Fred Gallagher and Rodney Caston. Megatokyo debuted on August 14, 2000, and has been written and illustrated solely by Gallagher since June 17, 2002. Gallagher's style of writing and illustration is heavily influenced by Japanese manga. Megatokyo is freely available on its official website. The intended schedule for updates was for postings twice a week, but new comics are typically posted just once or twice a quarter on non-specific days. In 2011, updates began being delayed further due to the health issues of Sarah Gallagher (Seraphim), Gallagher's wife. Megatokyo was published in book-format by CMX, although the first three volumes were published by Dark Horse. For February 2005, sales of the comic's third printed volume were ranked third on BookScan's list of graphic novels sold in bookstores, then the best showing for an original English-language manga.

Frederick M. Gallagher III is an American illustrator and web cartoonist. He is best known as the artist, co-creator, and now full owner of Megatokyo. He also goes by the name of Piro, the main character of Megatokyo, who he has stated is an idealized version of himself when he was in college. He took this name from that of the cat in the visual novel Kanon.