Astro Boy is the American title for the Japanese animated series Tetsuwan Atom (鉄腕アトム), first broadcast on Japanese television from 1963 to 1966. Astro Boy is considered to be the first true anime series. It was originally a manga series started in 1952 by Osamu Tezuka, the so-called "god-king of manga". After enjoying success abroad, Astro Boy was remade in the 1980s and again in 2003. For a while, in popularity Astro Boy was the Japanese equivalent of Mickey Mouse.

The animation series was produced by Musi Production, a studio established and headed by Tezuka.

Astro Boy is a science fiction series set in a future of robots, centered on the adventures of "Astro", a robot made to replace a dead boy but rejected by his "father" because he could not grow up like a real son. The series explored issues of racism, prejudice, true heroism, and loss.

In the original story, Astro Boy was created on April 7, 2003. On the same day in the real world, a city in Japan (Niiza of Saitama prefecture) granted Astro Boy a special citizenship. This is in contrast to the hardship Astro Boy went through in the fiction to be a part of human society, including obtaining a citizenship.

The original Tetsuwan Atom manga stories are now also available in English, published by Dark Horse Comics in a translation by Frederik L. Schodt. They follow the television series in using "Astro Boy" instead of "Tetsuwan Atom", as that is the name most familiar to English-speaking audiences. Even the new 2003 series in Japan uses "Astro Boy" as its moniker.