Dinh has defended pro-democracy activists and bloggers
A court in Vietnam has convicted four activists, including prominent human rights lawyer Le Cong Dinh, of trying to overthrow the Communist government.
The four men received sentences of up to 16 years on charges of subversion.
Dinh was sentenced to five years, while internet entrepreneur Tran Huynh Duy Thuc received the longest term.
The case has drawn strong criticism from rights groups abroad, who see it as a sign of an increasing clampdown on democracy and freedom of expression.
It has been a long time since the Communist regime last tried anybody on subversion charges, considered one of the most serious offences under Vietnam's criminal code, says the BBC's Nga Pham.
Nga Pham, BBC Vietnamese Service
This is perhaps the harshest punishment against democracy campaigners in recent years.
The arrests of these four dissidents have attracted much attention, mainly because of the high profiles of the accused, especially Le Cong Dinh.
This trial has been seen by many as an example of the government's intolerance to political dissent in the run-up to next year's Communist Party Congress.
The four accused - who were arrested in June - were initially charged with spreading anti-government propaganda.
But early last month, state prosecutors decided to bring more serious charges against them.
After a day-long trial, Le Cong Dinh, Tran Huynh Duy Thuc, Nguyen Tien Trung and Le Thang Long were all convicted of "activities aimed at subverting the people's administration".
Thuc received a 16-year sentence, Trung seven years, while Dinh and Long were sentenced to five years each.
Three of the four could have been sentenced to the death penalty.
Dinh rose to prominence representing Vietnam's interests in the "catfish battle" during which US farmers accused the Vietnamese of dumping cheap seafood on the US market.
In recent years, he has also defended some of Vietnam's leading human rights and democracy activists, including fellow lawyers Nguyen Van Dai and Le Thi Cong Nhan who have also been jailed for anti-government activity.