Who is the antagonist in The Amazing Spider-Man?

It depends on which "The Amazing Spider-Man" you're referring to! There are actually two major film franchises with that title:

For the original "The Amazing Spider-Man" (1960s-2010s comic series):

* There are many antagonists, as Spider-Man's rogues' gallery is incredibly large. Some of the most notable include:

* Doctor Octopus

* Green Goblin

* Venom

* The Lizard

* Electro

* Kraven the Hunter

For the 2012 "The Amazing Spider-Man" film series:

* The main antagonist in the first film (2012) is Dr. Curt Connors/The Lizard.

* The main antagonist in the second film (2014) is Electro.

You can tell me which "The Amazing Spider-Man" you're interested in, and I can give you more specific details about the antagonists!