Academy secretary Peter Englund said in an email Friday that the 82-year-old writer had declined the invitation, and that it's not yet clear who will represent her at the Dec. 10 award ceremony.
The academy announced last week that Munro had won the $1.2 million prize for this year, and called her a "master of the contemporary short story."
After the award was announced, Munro said she was delighted and ``just terribly surprised.''
She is the 110th Nobel laureate in literature and only the 13th woman to receive the distinction.
She's also just the second Canadian-born author to receive the honour after Saul Bellow in 1976. Though he was born in Lachine, Que., he moved to Chicago at age eight.
Munro has published more than a dozen collections of short stories since the 1960s, often focusing on the lives of girls and women from the towns and farming communities in her home region of southwestern Ontario.
--With files from The Canadian Press
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