The court sentenced two executives in Oktar's organisation, Tarkan Yavas and Oktar Babuna, to 211 and 186 years, respectively.
During the trial, which heard harrowing testimonies from victims of sexual abuse, Oktar denied being associated with Gulen and also insisted he was not the head of a "sex cult".
At a hearing in September, Oktar told a judge he had around 1000 "girlfriends", which he attributed to his "overflowing of love in my heart for women".
He also claimed on a separate occasion to be "extraordinarily potent".
One victim who gave evidence at the trial, and was identified only as CC for legal reasons, said Oktar repeatedly sexually abused her and other women.
The woman, who joined the cult aged 17, said some of the women raped by Oktar had been forced to take contraceptives afterwards.
When police raided Oktar's home they found 69,000 contraceptive pills, which he claimed were used for treating skin disorders and mental health issues.
Following his arrest in 2018, Turkish authorities demolished the villa he used as a studio for his evangelical TV channel, which claimed that Darwin's theory of evolution was false.
The channel, A9, began broadcasting in 2011 and was frequently condemned by Turkey's religious leaders, who took issue with him posing alongside heavily made-up and scantily dressed women.
Oktar wrote under a pen name a 700-page book advocating creationism, The Atlas of Creation, sending unsolicited copies to academics, libraries and members of Congress in the United States.
The book was mocked at the time for being riddled with basic scientific errors.
He also set up a website dedicated to criticising the BBC and after his arrest claimed that he was the victim of a British intelligence operation.
