Kolesnikova and another opposition activist, Maxim Znak, were charged with extremism and conspiring to "seize state power in an unconstitutional way" in a trial held in the capital Minsk behind closed doors, Belarusian state media Belta reported.
Znak, who is also a key member of the coordination council formed by opponents of Lukashenko's authoritarian government, was sentenced to 10 years in prison.
СNN:Belarus opposition figure and protest leader sentenced to 11 years in jail
Kolesnikova, a musician-turned-activist, was one of three women who joined forces last year to front the opposition's campaign against Lukashenko after prominent male opposition candidates were barred from the presidential race.
- CNN
The trio were the face of a protest movement that sent tens of thousands of Belarusians onto the streets to demand political change during the country's election. The demonstrators, as well as independent observers, alleged that the vote was rigged to extend Lukashenko's 27-year rule.
President Lukashenko, who denied electoral fraud, has faced sanctions from the US and other Western governments since claiming victory and launching a crackdown against opponents last year.
Kolesnikova was arrested last September and taken to the border, where she was ordered to leave the country. Instead, she reportedly ripped up her passport, refusing to be forced into exile.
Politically motivated conviction and shameful sentencing
The European Union denounced the verdict, while Britain's foreign minister called it an assault on defenders of democracy
The EU deplores the continuous blatant disrespect by the Minsk regime of the human rights and fundamental freedoms of the people of Belarus
- the EU's spokesperson said in a statement.
The United States condemned the "politically motivated conviction and shameful sentencing" of the two and called the charges against them bogus, Secretary of State Antony Blinken said
"These sentencings are further evidence of the regime’s total disregard for the human rights and fundamental freedoms of the people of Belarus,"
- Blinken said in a statement
Belarusian opposition politician Maria Kolesnikova, charged with extremism and trying to seize power illegally, forms a heart shape in handcuffs inside a defendants' cage as she attends a court hearing in Minsk, Belarus September 6, 2021
Footage from the Sputnik Belarus channel showed the two prisoners in a glass cage ahead of the verdict. Kolesnikova raised her handcuffed hands to make her trademark heart sign and smiled for the cameras.
Reuters: Kolesnikova was among tens of thousands of people detained after the protests began
Kolesnikova was among tens of thousands of people detained after the protests began. She was one of three women, all political novices, who joined forces to front last year's election campaign against Lukashenko after higher-profile male candidates were barred from standing.
ABC News:Kolesnikova refused to go into exile even as Lukashenko reasserted his grip
Last September, security forces abducted her off the streets in the capital Minsk and then drove her to the border with Ukraine, where they tried to forcibly deport her.
But Kolesnikova resisted the attempt, tearing up her passport to make her deportation impossible and refusing to go, despite knowing she faced certain imprisonment in Belarus.