Her husband Damian Lewis announced the news on Twitter.
Helen played the part of Polly Gray, the domineering matriarch of the Shelby family in Birmingham-based series Peaky Blinders.
He wrote: "I'm heartbroken to announce that after an heroic battle with cancer, the beautiful and mighty woman that is Helen McCrory has died peacefully at home, surrounded by a wave of love from friends and family.
"She died as she lived. Fearlessly.
"God we love her and know how lucky we are to have had her in our lives.
"She blazed so brightly.
"Go now, Little One, into the air, and thank you."
The Black Country Living Museum, where many of the Peaky Blinder scenes were filmed, expressed their sadness at the news of Helen's death on Twitter.
"So very sad to hear this news," said the Dudley attraction.
"Our thoughts are with Helen McCrory's family and friends."
Television presenter Dermot O'Leary paid tribute to Helen McCrory, tweeting: "Had the good fortune to meet and interview Helen McCrory a few times.
Had the good fortune to meet and interview Helen McCrory a few times.— Dermot O'Leary (@radioleary) April 16, 2021
A mighty talent, with always a hint of mischief. Really lovely company. Very sad news.
"A mighty talent, with always a hint of mischief. Really lovely company. Very sad news."
Comedian Matt Lucas, who worked with Helen McCrory on the FeedNHS campaign to supply food for NHS staff amid the pressures of the Covid-19 pandemic, tweeted: "Helen McCrory will be remembered not just for her remarkable stage and screen performances, but also for her selflessness and generosity.
Helen McCrory will be remembered not just for her remarkable stage and screen performances, but also for her selflessness and generosity. She and Damian were the motor driving FeedNHS, working tirelessly during the pandemic to raise millions for others. What a tremendous loss.— Matt Lucas (@RealMattLucas) April 16, 2021
"She and Damian were the motor driving FeedNHS, working tirelessly during the pandemic to raise millions for others. What a tremendous loss."
Actor Michael Sheen, who worked with Helen McCrory in ITV drama Quiz, paid tribute to the late actress.
He tweeted: "So funny, so passionate, so smart and one of the greatest actors of our time.
"From the first moment I met her when we were just kids it was obvious she was very special.
"It was an honour to work with her and know her. Much love to Damian and her family. Heartbreaking."
Actor Jim Howick, who worked with Helen McCrory and her husband Damian Lewis on the 2015 comedy film Bill, tweeted: "This is so shocking and sad. Helen along with Damien were both terrific fun on Bill.
"She was so generous with her time and her performance. I urge everyone to listen to her Desert Island Disks. What a talent we have lost."
Rev Richard Coles was among those paying tribute. He wrote on Twitter: "Very sorry to hear of the death of Helen McCrory, such a brilliant actor; heartfelt condolences to Damian Lewis, their children, and all who loved her."
Actor and director Noel Clarke said: "RIP #HelenMcCrory you were the best and always lovely to me. It was a pleasure to work with you. Love ya. Blessings to Damian and the family."
Actress Michelle Collins tweeted: "I'm really shocked so so sad I had the pleasure of meeting her and briefly worked with her, she certainly was a Tour de force, clever, charming and fierce and a brilliant actor my heart goes out to Damian and her family, bloody cancer I hate you!!"
The actor Kevin McKidd, who starred opposite Helen McCrory in the 2000 TV miniseries Anna Karenina, tweeted: "I am utterly heartbroken to hear this.. Damian I'm sending you and the family all my love and warmth at this time.
"Helen, we love you. Your talent, humanity and passion for life will be remembered by me and everyone your life touched with deep gratitude. Rest In Peace dear one."
The Wizarding World Twitter account, home to the Harry Potter franchise, tweeted: "We are deeply saddened to hear of the passing of our beloved Helen McCrory, who played Narcissa Malfoy with such depth and brilliance in the Harry Potter film series.
"She was a wonderful actor and a very dear friend; Harry Potter fans will miss her very much."
Comedian John Bishop tweeted: "I am shattered to hear this news. Helen was a beautiful supportive person to those of us who had the honour to know or work with her. The world has just lost some of its sparkle.
"My heart goes out to Damian and the family, no words of condolences will ever be enough."
Helen attended school in Hertfordshire, then spent a year living in Italy, before returning to London to study acting at the Drama Centre.
She and Lewis married in 2007 and share a daughter Manon, born in 2006, and son Gulliver, born in 2007.