Ravetch died Sunday of pneumonia at Cedars-Sinai Medical Center in Los Angeles, said his nephew Michael Frank.
In a screenwriting collaboration that began with the 1958 film "The Long, Hot Summer," Ravetch and Frank wrote the scripts for more than a dozen other films, including "The Sound and the Fury," "The Dark at the Top of the Stairs," "Hombre," "The Reivers," "The Cowboys," "Conrack," "Murphy's Romance" and "Stanley & Iris."
They shared Oscar nominations in 1964 for their screenplays for "Hud," a drama set in modern Texas and starring Paul Newman as the ruthless son of an elderly rancher, and in 1980 for "Norma Rae," a drama starring Sally Field in her Oscar-winning role as an impassioned Southern union organizer.
Eight of the Ravetch-Frank Jr. screenplays, including "Hud" and "Norma Rae," were directed by the late Martin Ritt.
"I don't know of any better screenwriters than Irving Ravetch and Harriet Frank Jr.," Ritt said in the foreword to the 1988 book "Hud, Norma Rae and the Long, Hot Summer: Three Screenplays by Irving Ravetch and Harriet Frank Jr."
"They are absolutely the best, on every level," said Ritt. "I've enjoyed collaborating with them, and I know that we've done work as good as any that has been done in Hollywood."
Mark Rydell, who directed "The Reivers" and "The Cowboys," told The Times on Tuesday that he had "the greatest reverence" for Ravetch, who "was not only a screenwriter but a teacher and taught me many things I needed to know."
"The first thing I did for them was their adaptation of William Faulkner's 'The Reivers,'" recalled Rydell. "I didn't change a word; that's how brilliant their screenplay was.
"It was so thrilling to be exposed to Irving and Harriet, who are, in a sense, the deans of American screenwriting. You can't get more skilled or insightful or compassionate than they are."
In 1988, Ravetch and Frank Jr. received the Screen Laurel Award for lifetime achievement from the Writers Guild of America, West.
Ravetch was born in Newark, N.J., on Nov. 14, 1920. His father, a pharmacist who became a rabbi, was an immigrant from Russia; and his mother, a teacher of Hebrew, was born in what is now Israel.
Suffering from severe asthma as a child and prone to getting pneumonia every winter, Ravetch was sent to live with an aunt in Los Angeles in 1930. His family did not join him until several years later.
He attended Long Beach City College and graduated from UCLA, where he majored in English literature. Because of his asthma, he served only briefly in the Army during World War II.
Ravetch was writing short subjects at MGM in 1945 when he met Frank in the junior writing program at the studio, where her mother was a story editor. Immediately taken with Frank, Ravetch paid the man in the office next to hers $50 to give Ravetch his office.
They were married in 1946 and maintained separate writing careers during the early years of their marriage. During that time, Ravetch also wrote plays in an attempt to launch a career on Broadway that, he later said, "bombed ferociously."
Ravetch and Frank began their collaboration by co-writing the story for the 1955 Randolph Scott western "Ten Wanted Men."
In a 1979 interview with The Times, Frank said she and her husband had "a line-for-line collaboration," one that began with weeks of talking everything out, taking notes and speaking every line.
"I know writers who work separately and then get together later on — in fact, that's the usual way — but that destroys the point of collaboration," Ravetch said. "When we come to a tangle, we can stop until it's worked out."
Added Frank: "We have two energies working. But you can't collaborate unless the result is seamless. Of course, we have disagreements, but they become a professional, not a personal, thing."
They enjoyed their working relationship.
"A marriage that serves a collaboration has got to be good and vice versa," said Frank.
"It was a very good decision to work together," said Ravetch. "Have I told you that, dear?"
"Yes, every day," said Frank.
In addition to his wife of 63 years, Ravetch is survived by his sister, Merona Ravetch Frank; and his brother, Herbert Ravetch.
Services will be private.