Five others were given suspended death sentences, according to state broadcaster CCTV- a penalty normally commuted to life in prison- with another four jailed for varying terms.
In one incident, assailants armed with knives and explosives attacked a train station in the regional capital Urumqi in April, killing one person and wounding 79 on the final day of a visit by Chinese President Xi Jinping. Two assailants also died.
The following month 39 people were killed, along with four attackers, and more than 90 wounded when assailants threw explosives and ploughed two vehicles through a market in Urumqi, state media said.
The sentences, handed down by the Intermediate People's Court in Urumqi, bring the number of death penalties or executions announced for Xinjiang-related violence to around 50 since June.
They are part of a harsh crackdown Beijing has imposed on violence in the vast resource-rich area, deep in China's far west.
Over the past year at least 200 people have died in a series of clashes and increasingly sophisticated attacks in the region and beyond it.
Beijing has blamed such incidents on "separatists" and "terrorists", while rights groups say that harsh police treatment of Uighurs and government campaigns against religious practices such as the wearing of veils have led to violence.
China defends its policies, arguing that it has boosted economic development in the area and that it upholds minority and religious rights in a country with 56 recognized ethnic groups.
'Setting off explosives'
Photos distributed by CCTV on its official microblog showed several of the defendants seated in a row at the front of a courtroom. The young men were clad in brightly-coloured prison vests and had their heads shaven.
For the train station attack, it said, two defendants were condemned to die, three given suspended death sentences and one given five years in prison.
For the market incident, another six were given death sentences, two given suspended death sentences and one life in prison, it added. Two received 10-year terms.
The charges included "organizing, leading and taking part in terror organizations", "setting off explosives" and "endangering public security by dangerous means", according to the People's Daily. Calls by AFP to the Urumqi court went unanswered.
Hundreds of people have been jailed or detained on terror-related offences in Xinjiang following the May attack. Police have shot dozens of locals in other clashes over the summer.
Authorities tightly restrict access to Xinjiang, and official reports on incidents in the region are difficult to independently verify.
The crackdown in Xinjiang has extended to academics such as prominent Uighur scholar Ilham Tohti, who in September was sentenced to life in prison for "separatism". Several of his students were subsequently tried in secret for the same offence.
The targeting of Tohti and his students has been decried by the US and European Union as well as international rights groups as part of an effort to silence criticism of government policies in the region.
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