The Tajik government banned Hizb ut-Tahrir in 2001. The group was arrested last year.
The leader of the banned Hizb ut-Tahrir movement in Tajikistan, Yusuf Khafizov, has been sentenced to 18 years in prison.
Seven other active members of the pan-Islamic movement received prison terms ranging between six and 17 years.
The defendants were all found guilty of inciting ethnic and religious hatred and attempting to overthrow the government.
Lawyers and relatives of the convicted men say they plan to appeal their cases.
One of the defendants’ relatives, Ulmas Boiboboev, told RFE/RL that the group’s plan was to build an Islamic state but only through political means and without using violence.
A wide-ranging crackdown on religious freedom is underway, with authorities closing mosques and harassing men with beards.
During the first 10 days of January, officials in the Tajik capital Dushanbe closed a mosque every day, local media outlets reported. Officials contend the mosques failed to register in accordance with legislation adopted in 2009. But imams insist that they tried to go through the registration process only to have their applications rejected for unspecified reasons.