A mastodon is a large, elephant-like mammal of the extinct genus ''Mammut'' (formerly ''Mastodon''). Mastodon may also refer to:

Animals

* Gomphotheriidae, an extinct family of elephant relatives.

Software

* Mastodon (social network), open-source software for federated micro-blogging, similar to Twitter.

Places

* Mastodon Township, Michigan

Vehicles

* Mastodon (steam locomotive), ''Mastodon'' (steam locomotive) (CPR #229), the very first steam locomotive of the 4-8-0 wheel arrangement. * A nickname for the 4-10-0 wheel arrangement.

Music

*Mastodon (band), an American heavy metal band. **Mastodon (album), ''Mastodon'' (album), a box set released by the band's former label.

Comics and games

* Mastodon (Weapon X), a comic book character who plays a minor role in the backstory of Wolverine. * Mastodon (New Universe), the code-name of one of members of the DP7 comic book superhuman group. * Mastodon, a gigantic quadrupedal walker in the game ''Command & Conquer 4: Tiberian Twilight''.

Sport and athletics

* Purdue Fort Wayne Mastodons, the athletic teams and mascot of Purdue University Fort Wayne.