- 1984 — Megatron, leader and sometimes founder of the Decepticons from Generation One. For Toys of this character, see Megatron (G1) toys
- 1996 — Megatron, a Predacon criminal and architect of the theft of the Golden Disk turned ruler of Cybertron. Later became the leader of the Vehicons and was split into Savage/Noble and the Grand Mal in Beast Wars and Beast Machines. Yeesss.
- 2004 — Megatron, the first Decepticon leader having departed Cybertron long ago with Rodimus and eventually seeking a peaceful existence.
- 2007 — Megatron, the former Lord High Protector of Cybertron who gets a jonesing for the AllSpark and sparks a motion picture.
- 2008 — Megatron, the leader of the TransTech Decepticons.
- 2010 — Megatron (Uniend), the commander of the Decepticons searching for Dark Energon in War for Cybertron and Prime.
Megatron is not to be confused with:
- Straxus, a Decepticon commander who temporarily inhabited Megatron's body (or a version of it, it's complicated) from the Generation One comics.
- The Megatron Military, Galvatron's legion of Megatron clones from The Transformer manga series.
- The Megatron statue, a massive stone statue of the Unicron Trilogy character.
- Megaplex, a duplicate of Megatron designed to fool his enemies from the Generation One continuity.
- Mechatron, a Beast Rider from Beast Machines.
- Megabolt, Decepticon emissary, whose alternate form mimics the Big Floating Head headquarters of Beast Wars Megatron in the Beast Machines cartoon, from Robots in Disguise/Universe.
- Megastorm, younger brother of Galvatron from Beast Wars II.
- Megastar, Robots in Disguise Megatron's starship/base.
- Megazarak, an alternate dimension's version of Megatron from Transformers Universe.
- Mega-Dinobot, the combined form of Unicron Trilogy Grimlock and Swoop from Energon.
- Mega-Octane, leader of the Decepticon Commandos from Robots in Disguise, who looks exactly like the Combaticon leader Onslaught.
- Megatronus Prime, the original name for the The Fallen (multiversal singularity).
Many versions of Megatron eventually upgrade their bodies and change their name to Galvatron.