Chapman was sentenced to between 20 years and life in jail after shooting the Beatles star in New York in 1980.
He was eligible for parole in 2000 and Lennon's widow has continuously opposed his release. The 55-year-old will face another parole board hearing early next month.
Ono's lawyer Peter Shukat told the New York Daily News: "Her position has not changed."
Robert Gangi, who is the head of prisoners' rights group Correctional Association of America, added: "Given that he committed a high-profile crime and he killed one of the most famous and most beloved figures literally in the world, it's highly unlikely three parole commissioners would vote to grant him release."
