In a tweet, Davis said the show was "one of the greatest rides of my life!"
"Viola Davis made television history with her unforgettable portrayal of iconic female antihero Annalise Keating," ABC Entertainment President Karey Burke said in a statement, according to EW.com. "I am eternally grateful to her, Pete Nowalk, and Shondaland for creating and bringing to life such a smart, sophisticated, and groundbreaking series that has long been an integral part of Thursday nights on ABC."
According to The Hollywood Reporter, the final season will look at Keating's class as they make their way through their final semester in law school.
"Deciding to end this series was a brutal decision, but ultimately the story tells you what to do — as it did here," Nowalk said in a statement, according to People. "For me, Annalise Keating's journey has always had a clear ending. Knowing I have 15 episodes left to finish her story, and the chance to give all the characters their own killer endings, is a gift rarely given to a series creator, and I'm grateful to ABC and ABC Studios for the opportunity and creative freedom.
“I am so thankful to the brilliant cast, writers and crew for dedicating themselves to the most rewarding experience of my career over the last six years.
"I also want to thank our fans. The only reason this show exists is because of your loyalty and enthusiasm. I can’t wait for you all to see how it ends, with twists and turns and all the craziness we love to create every Thursday night. Buckle up.”
The final season of "How to Get Away with Murder" will consist of 15 episodes and premieres Sept. 25 at 10 p.m. ET on ABC. Watch the trailer for the final season below.