Godse died at his home in the city of Pune late on Saturday, the Press Trust of India (PTI) news agency quoted his son Nana Godse as saying. No cause of death was given and family members could not immediately be reached.
Godse, whose brother Nathuram shot Gandhi, who led India to independence through "passive resistance", served 16 years in jail for his involvement in the killing in 1948.
Godse remained unrepentant for his role in killing Gandhi, who fought for equality in a nation sharply divided by caste.
"He was a very cruel person for the Hindus," Godse said of Gandhi in an interview with The Associated Press in 2003.
Godse believed that the independence leader, whose full name was Mohandas Karamchand Gandhi, turned his back on Hindus, allowing British India to be divided in 1947 into India and Pakistan.
To Godse and his band of Hindu extremists, Gandhi's calls for non-violence were part of a plot to set Hindus and Muslims against each other.
Last surviving conspirator
Godse was the last surviving member of the group that killed Gandhi on 30 January 1948.
"We did not want this man (Gandhi) to live. We did not want this man to die a natural death, even if 10 lives were to be lost for that purpose"
Gopal Vinayak Godse
That evening, Gandhi, 78, was walking towards the prayer ground in the garden of a home in New Delhi when Nathuram Godse stepped in front of him and fired three shots.
Nathuram Godse and another man were hanged for the murder.
"We did not want this man to live," Godse said in the interview. "We did not want this man to die a natural death, even if 10 lives were to be lost for that purpose."
After his release from jail, Godse lived in Pune, largely living off royalties from books he wrote on Gandhi and the assassination.
He is survived by his wife, Sindhu Godse, a son and two daughters, PTI reported.