The title was revealed at a Star Wars celebration event in Chicago, while a teaser trailer was posted on Twitter with the words: "Every generation has a legend."
Director JJ Abrams said the movie is set some time after previous instalment The Last Jedi.
The Rise of Skywalker is due to be released later this year.
Despite his apparent death at the end of Episode VI, Return of the Jedi, Emperor Palpatine seems to be making a comeback.
His sinister cackle is heard at the end of the trailer and Ian McDiarmid, who plays the character, strolled on stage to loud applause at the announcement.
The two-minute trailer, the first footage seen from the new film, also features a brief glimpse of Princess Leia, played by the late Carrie Fisher.
She embraces Rey (Daisy Ridley), while Luke Skywalker's voice is heard saying: "We'll always be with you. No one's ever really gone."
Fisher died in 2016 but the filmmakers were able to use previously unseen footage from The Force Awakens.
Abrams told a US "Star Wars Celebration" event in Chicago it was a "weird miracle" to be able to continue Princess Leia's story.
"Every day it hits me that she's not here, but it's so surreal because we're working with her still," he said.
"She's so alive in the scenes and the craziest part is how not crazy it feels. Princess Leia lives in this film in a way that's kind of mind-blowing for me."
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