Hamtaro, known in Japan as Trotting Hamtaro (とっとこハム太郎, Tottoko Hamutarō), is a Japanese children's manga and storybook series created and illustrated by Ritsuko Kawai about a hamster named Hamtaro. The manga was first published in Shogakukan's Shōgaku Ninensei (Second Grade) magazine in April 1997; more Hamtaro stories would later be added into the other grade-level magazines, as well as in Ciao. The series focuses on a hamster named Hamtaro, who has a variety of adventures with other hamsters known as the "Ham-Hams" ("Hamuchans" in the Japanese version). Viz Media published the manga adaptations and storybooks in English.

Multiple anime adaptations were produced by TMS Entertainment and aired on TV Tokyo. The first series was dubbed in English by The Ocean Group.

The series revolves around a hamster named Hamtaro, who is owned by a young girl named Laura Haruna (Hiroko Haruna in the Japanese/Original version). Curious by nature, he ventures out each day to make friends and go on adventures with a clan of fellow hamster friends known as The Ham-Hams. The Ham-Hams meet at a special clubhouse built by Boss ("Taisho").

There are three manga about Hamtaro, A Home for Hamtaro, Hamtaro Gets Lost, and Jealous Hamtaro. In the first two, Hamtaro's owner is named Yukari while in the latter, her name is Amy.

In Japan, Hamtaro aired three anime series, released four films, several specials, many video game/DVD releases, and merchandise. By 2002, the franchise had generated $2.5 billion in merchandise sales. The success was not paralleled in the United States, however, with only the first series, some special episodes, three video games (though two others were released in Europe), and limited merchandise. On 23 February 2011, it was announced that Hamtaro would be receiving a series titled Trotting Hamtaro Dechu!.

The Hamtaro franchise has multiple video game titles with independent storylines. These titles include adventure and educational games that can be found for PC, Game Boy Color, Game Boy Advance (GBA), and the Nintendo DS consoles.

On 26 July 2020, a group of more than 2,000 protesters in Bangkok called the Free Youth Movement led a protest against the government of Thailand which involved singing the theme song for Hamtaro with modified lyrics to say "The most delicious food is taxpayers' money. [...]Dissolve the parliament! Dissolve the parliament! Dissolve the parliament!" Other student protests during the same week continued to use Hamtaro as a symbol for the government's "feasting on taxpayer's money," and have involved groups running in circles, as if in hamster wheels, while singing the modified version of the jingle.

In TV Asahi's poll of the Top 100 Anime, Hamtaro came in 68th.