Wilson died at Yale New Haven Hospital, surrounded by loved ones, her friend Elizabeth Morton told CNN.
"She had just turned 94 a few weeks ago and had rapidly declining health since then -- she died peacefully," Morton said. "She died knowing how loved she was."
In a stage, film and television career that began with an uncredited bit part on Alfred Hitchcock's 1946 film "Notorious," Wilson often played authority figures -- mothers, judges, administrators -- though they were usually unsympathetic types.
She was Dustin Hoffman's mother, Mrs. Braddock, in "The Graduate," generally ignorant of her son's emotional turmoil. She was Roz Keith, the office busybody, in "9 to 5," singularly unhelpful to the secretaries and administrators played by Jane Fonda, Lily Tomlin and Dolly Parton.
And in "Quiz Show," she played Dorothy Van Doren, the upright mother of Ralph Fiennes' Charles Van Doren -- again, clueless to her son's angst.
Wilson had more opportunity to show her range on stage. Her first Broadway role was in William Inge's "Picnic" in 1951. She won a Tony in 1972 for her performance in David Rabe's "Sticks and Bones" and Obies for performances in 1979's "Taken in Marriage" and 1986's "Anteroom."
She was an occasional presence on television, with roles in many TV movies and parts in the series "East Side/West Side" and "Doc." She guested on such series as "All in the Family," "Murder She Wrote" and "Law & Order: Criminal Intent."
Director Mike Nichols was a frequent collaborator. She was in four Nichols films, including "The Graduate" and "Catch-22," and three plays.
"Every director has a different technique, and Mike's great gift is in casting," she told Connecticut Magazine in 2012
. "He knows who's right for a particular role, and he's not controlling."
Though she was never a household name, she knew that her value was in being different. She had an opportunity to become a starlet when she started out, she told Connecticut, and declined.
"A movie company came to see the play I was in and offered me a contract. But the deal was, my nose was too big and they wanted me to have surgery. My jaw was crooked, and I'd have to have that fixed, too," she said. "I don't know how I managed to do this, but I said, 'I don't think so.' Imagine! I can't believe I had the wisdom. But I know people who did that surgery, and they all looked alike."
Wilson's last part was as Sara Delano Roosevelt, Franklin Roosevelt's mother, in 2012's "Hyde Park on Hudson."