Max Bokaev and Talgat Ayan were both arrested in April as protests against proposed land code amendments rippled across the vast Central Asian country, threatening the 27-year rule of strongman President Nursultan Nazarbayev.
The court in the western city of Atyrau found the pair guilty on charges of inciting social tensions and spreading false information during the spring protests, Kazakhstan's supreme court said in a statement.
Their sentences come after another court sentenced beer magnate Tokhtar Tuleshov to 21 years in prison earlier this month for his purported role in masterminding the protests in order to overthrow Nazarbayev.
Thousands participated in the countrywide demonstrations against amendments that would have changed the maximum length of leases on land for foreigners from 10 to 25 years.
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New York-based Human Rights Watch reported that hundreds of people were detained in the build-up to a planned nationwide protest on May 21.
The same organisation last month called on Kazakh authorities to stop the trial of Bokaev and Ayan and free both men.
Nazarbayev, 76, signed off on a moratorium preventing implementation of the land reform through 2021 in a rare concession to political opposition.
This month the national bank announced the issue of bills worth 10,000 tenge (nearly USD 30) which will bear his image while Nazarbayev himself knocked back a proposal by lawmakers to rename the Kazakh capital Astana in his honour last week.
Land policy is highly sensitive in ex-Soviet Central Asia where many recall the privatisations of the 1990s after the collapse of the USSR with bitterness.