Three of those executed had been convicted of an attack in Tiananmen Square in Beijing last October, in which five people died, Xinhua said.
The others were found guilty of crimes including bomb-making and arson.
The government has accused separatist militants based in Xinjiang of carrying out a string of recent attacks.
Xinjiang is the traditional home of Muslim Uighurs, who speak a distinct language and have different customs to the majority Han population elsewhere in China.
Huseyin Guxur, Yusup Wherniyas and Yusup Ehmet were "deprived of political rights for life" because of their role in the deadly car crash on Tiananmen Square in October 2013, Xinhua said.
"They masterminded the terrorist attack," the news agency added.
In the incident, a car rammed into bystanders on the politically important Beijing square before bursting into flames.
Two tourists died, along with three of the attackers.
Xinhua named some of the other men who were executed along with the Tiananmen attack perpetrators:
Dilxat Raxit, a spokesman for the World Uighur Congress exile group, called the executions "a typical case of the law serving political ends".
Chinese officials often attribute attacks in Xinjiang to Uighur separatists, accusing them of seeking to establish an independent state called East Turkestan.
Beijing has recently blamed them for an attack in May at a market in Urumqi, that left at least 31 people dead.
It also accused them of being behind a mass knife attack in the southern province of Yunnan in March, in which 29 were killed and more than 130 injured.
Uighur leaders deny they are co-ordinating a terrorist campaign.
They say the government's repressive policies in Xinjiang have provoked the unrest.
Who are the Uighurs?
China has executed eight people in the north-western region of Xinjiang, for what it calls "terrorist" attacks, reports the state news agency Xinhua.