The sentencing of Liu Xiaobo, after he called for sweeping political reforms and an end to Communist Party dominance, also drew diplomatic criticism, with the United States saying it went against international norms.
Liu was the co-author of an unusually direct appeal for political liberalization in China called Charter 08. He was detained just before it was released last December. More than 300 people, including some of China's top intellectuals, signed it.
The verdict was issued at the No. 1 Intermediate People's Court in Beijing after a two-hour trial Wednesday in which prosecutors accused Liu of "serious" crimes.
The vaguely worded charge of inciting to subvert state power is routinely used to jail dissidents. Liu could have been sentenced for up to 15 years in prison under the charge.
A San Francisco-based human rights group, the Dui Hua Foundation, said it was the longest sentence that it knew of since the crime of inciting subversion was established in 1997.
The United States and European Union have repeatedly urged Beijing to free Liu.
"We are deeply concerned by the sentence of 11 years in prison announced today," Gregory May, first secretary with the U.S. Embassy, told reporters outside the courthouse. May was one of a dozen diplomats stopped by authorities from attending the trial and sentencing.
"Persecution of individuals for the peaceful expression of political views is inconsistent with internationally recognized norms of human rights," May said.
Foreign Ministry spokeswoman Jiang Yu told reporters this week that statements from embassies calling for Liu's release were "a gross interference of China's internal affairs."
New York-based Human Rights Watch said the ruling showed the government would be taking a hard line against human rights activists in the year ahead.
"This verdict is also an explicit warning from the government to China's intellectuals, civil society activists and human rights defenders that the state will severely punish those who the government perceives as a threat to its monopoly on power," said the group's Asia researcher, Phelim Kine.
Another rights group, Chinese Human Rights Defenders, said the ruling shows the government is bent on thwarting any reform and is using the courts to silence its critics.
"Giving such a long sentence to one of China's most prominent dissident intellectuals is a clear sign that the Chinese government is further hardening its stance against political dissent," said Renee Xia, the group's international director.
The defendant's wife, Liu Xia, told The Associated Press that her husband planned to appeal. "Our lawyers are going to talk to the authorities next week about the appeal," Liu Xia said. She said her husband looked calm and asked about family and friends during a brief meeting after the sentencing.
Liu is the only person to have been arrested for organizing the Charter 08 appeal, but others who signed it have reported being harassed.
Abolishing the law on inciting to subvert state power is among the reforms advocated in Charter 08. "We should end the practice of viewing words as crimes," the petition says.
Liu, a former Beijing Normal University professor, spent 20 months in jail for joining the 1989 student-led protests in Tiananmen Square, which ended when the government called in the military - killing hundreds, perhaps thousands.
Charter 08 demands a new constitution guaranteeing human rights, the open election of public officials, and freedom of religion and expression. Some 10,000 people have signed it in the past year, though a news blackout and Internet censorship have left most Chinese unaware that it exists.