Twilight is about this teenage girl, Bella Swan, who lives in Forks, Washington, and she meets these vampires at her new high school who are very beautiful beyond words. She is introduced to them, they are: Edward Anthony Mason Cullen, Alice Cullen, Carlisle Cullen, Emmett Cullen, Esme Cullen, Rosalie Hale, and Jasper Hale. They all end up in this huge fight with other vampire's with the Werewolves on their side (the Cullens' side).
Vampire Academy is about a vampire princess who needs to be protected at all times from the dangerous vampires who NEVER die. The princesses friend is dedicated to a life of protecting her best friend from the dangerous vampires. After two years of freedom the princess and her friend are caught and dragged back to Vladimer's Academy where they have to finish their education.
Similarities- These are both about vampires who have other vampires that they don't get along with, also they are similar because they both have sexy vampires in them. (Vampire Academy's guy's are better in my opinion!)
Differences- They differ a lot, Twilight has vampire's that sparkle for Pete's sake!! Vampire Academy at least has REAL vampires that don't sparkle!! Vampire Academy doesn't have werewolves like Twilight does, and Twilight's vampire's have special powers.
