Author Philip Pullman remembered her as "a warm and generous human being", while Tracy Chevalier said she was "a graceful, elegant writer and person."
Dunmore won the first Orange Prize for women's fiction in 1996 for her novel A Spell of Winter.
Publisher Penguin Random House said it was "devastated by the loss of one of our best-loved authors".
Bloodaxe Books, which published Dunmore's first poetry collection, The Apple Fall in 1983, said it was "immensely saddened" by her passing.
Born in the Yorkshire town of Beverley in 1952, Dunmore also wrote books for children, short stories and translations.
Her most recent novel, Birdcage Walk, was published in March.
Dunmore was diagnosed with cancer while writing her final novel and wrote movingly about her illness earlier this year.
"The ground beneath my feet has never been more uncertain," she wrote in The Guardian. "But what is sure is... there is no vagueness about my mortality.
"I may be ill but I'm also warm and sheltered, surrounded by family and friends."
Dunmore also spoke about her illness on Radio 4's Open Book, saying she hoped her work would be read by her loved ones after her death.
"One of the things that does please me is that my grandchildren will be able to get to know me... through reading my books," she told Mariella Frostrup.
Penguin Random House, who announced Dunmore's death, said she was "an inspirational and generous author" known for "championing emerging voices and other established authors."
Her editor, Selina Walker, remembered her as "an exceptional person and an exceptional novelist [with] a legacy of exceptional novels".
Dunmore leaves behind her husband, Francis Charnley, three children/stepchildren and three grandchildren.
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Tributes have been paid to the Orange Prize-winning writer Helen Dunmore, who has died of cancer at the age of 64.