Accepting an award on behalf of John Lennon (search) last month, Ono said Lennon had sometimes felt insecure about his songs, asking "why they always cover Paul's songs and never mine."
"I said, `You're a good songwriter, it's not June with spoon that you write.'"
After reports of the apparent slight circulated, Ono apologized in the latest issue of Rolling Stone magazine, now on newsstands.
"I certainly did not mean to hurt Paul, and if I did, I am very sorry," she says.
McCartney has sometimes clashed with Ono, Lennon's widow.
She objected when McCartney reversed the traditional "Lennon-McCartney" songwriting credit on his 2002 album, "Back in the U.S." Ono's spokesman accused him of attempting to "rewrite history."
McCartney had earlier complained that Ono wouldn't let him take credit for "Yesterday," a song written entirely by McCartney.