A statement posted to the actor's Twitter account said Boseman was diagnosed with Stage 3 colon cancer in 2016, but despite medical treatment, it had processed to Stage 4. He had never spoken publicly about his diagnosis.
"A true fighter, Chadwick persevered through it all, and brought you many of the films you have come to love so much," his reps said.
Boseman died in his home with his family by his side, they added.
Kevin Feige, the head of Marvel Studios, called Boseman's death "absolutely devastating."
"He was our T’Challa, our Black Panther, and our dear friend," Feige said in a statement. "Each time he stepped on set, he radiated charisma and joy, and each time he appeared on screen, he created something truly indelible. He embodied a lot of amazing people in his work, and nobody was better at bringing great men to life.
"He was as smart and kind and powerful and strong as any person he portrayed. Now he takes his place alongside them as an icon for the ages."
Born in Anderson, South Carolina, Boseman studied at Howard University before landing at the Schomburg Junior Scholars Program in Harlem as a drama instructor.
He eventually moved to Los Angeles to pursue acting, and earned multiple roles in film and television. His career took a major upswing with lead roles in the movies 42 (2013), Get on Up (2014), and Marshall in 2017 before he entered the Marvel Studios cinematic universe as T'Challa, king of the fictional African nation of Wakanda, in Black Panther in 2018. That award-winning film went on to gross more than $1.3 billion worldwide and became the first superhero movie to get an Oscar nomination for Best Picture.
He most recently appeared in Spike Lee’s Da 5 Bloods as a US freedom fighter in the Vietnam War.
News of his death sparked an outpouring of grief and remembrances on social media, including from his Avengers costar Mark Ruffalo, who said on Twitter, "it was the highest honor getting to work with you and getting to know you."
"What a generous and sincere human being. You believed in the sacred nature of the work and gave your all," he added. "Much love to your family. And much love from all of us left here."
Black Panther was considered to be a Hollywood game-changer, proving that a big-budget film with a predominantly Black cast and Black director could succeed at the box office.
In an interview with Esquire about the impact of the film's success, Boseman said he had noticed some change in the industry.
"I’ve seen a willingness of production companies and studios to castings in a way that they wouldn’t normally do," he said. "You can’t make certain statements about a Black lead, or a Black cast, or having a certain number of people of color — it’s not just Black actors — anymore. In fact, it’s been proven that audiences want to see difference. They want to see variety and a world that reflects them whether it be race, gender, or sexuality. They want to see those things, so I think people are looking for opportunities in storytelling now."
Still, he said there was more progress to be made.
"There are a lot of people that haven’t broken through yet, and who are still trying to find their way and trying to get through certain prejudices," he told the magazine. "I have to acknowledge that, but they have more opportunities to do it."
Correction: Chadwick Boseman died at age 43, his publicist confirmed to BuzzFeed News. An earlier version of this post misstated his age as 42.
Correction: Black Panther was the first superhero movie to receive an Oscar nomination for Best Picture. A previous version of this post said it was the first superhero movie to get an Oscar nomination.