The court sentenced the men on Monday to 14 to 20 years in prison for their role in a protest in May in which witnesses say hundreds of people died.
The United States condemned the ruling and said it was considering sanctions against Uzbekistan, while the European Union banned arms sales to the Central Asian country.
"These convictions are based on evidence that isn't credible and a trial that isn't fair," State Department spokesman Adam Ereli said.
But President Islam Karimov received a warmer reception in Moscow, where he and Russian President Vladimir Putin signed a pact pledging mutual help in fighting security threats.
"The court has found the accused guilty ... in particular of terrorism, attempts to overthrow the constitutional order, aggravated murder and the seizure of hostages," judge Bakhtyor Jamolov told the court.
Witnesses in Andizhan on 13 May, including a Reuters reporter, said Uzbek troops fired at a crowd of men, women and children who had gathered in the main square after armed men broke 23 local businessmen out of jail.
Troops killed hundreds of people and shot dead some of the wounded, eyewitnesses told Reuters at the time.
The bodies of those killed in the
shooting piled up in the square
The authorities say 187 people died - mainly "foreign-paid terrorists".
The 15 men on trial in Tashkent, who all pleaded guilty, stood with heads bowed inside a metal cage for five hours as the judge read a narrative supporting the official view of events.
He said the accused received "terrorist" training in neighbouring Kyrgyzstan and staged an uprising in Andizhan as part of a plot to set up an Islamic caliphate in Uzbekistan.
Jamolov said Western media in Andizhan on 13 May helped the "terrorists". His summing up repeated what prosecutors had told the court and the accused had said in their confessions.
The trial, which started in September, featured dozens of witnesses who supported the official line.
Andrea Berg, a researcher for New York-based Human Rights Watch, said the trial raised serious concerns.
"It was hard to believe that some pressure was not put on the defendants," she told reporters outside the court.
Islam Karimov views Russia as
important for regional stability
"We think this was a show trial."
Berg noted that no relatives of the accused were allowed into the courtroom, which was filled with men who had been brought there in a bus.
The West has criticised Karimov for using indiscriminate force to quash the Andizhan revolt, and the EU has banned arms sales and imposed a one-year visa ban on 12 top Uzbek officials.
"The (EU) Council decided to adopt these measures in the light of the excessive, disproportionate and indiscriminate use of force by the Uzbek security forces during the Andizhan events and following the refusal of Uzbek authorities to allow an independent international inquiry," a statement said on Monday.
The EU arms embargo covers arms, military equipment and "other equipment that might be used for internal repression".
"It was hard to believe that some pressure was not put on the defendants. We think this was a show trial"
Human Rights Watch
Asked if the United States would follow the EU's sanctions, Ereli said: "We have this under consideration."
In July, Uzbekistan gave the United States 180 days to leave a Soviet-era base the Pentagon had used for US operations in Afghanistan after Washington criticised its violent suppression of the uprising.
Moscow, keen to strengthen its position in the ex-Soviet world, has backed Karimov, who had poor relations with Moscow before the Andizhan events but has since softened his stance.
"The strengthening of Russia's position in Central Asia is a solid guarantee of stability in the region," Karimov said after signing the pact.
The treaty envisages that one side could start consultations to coordinate practical steps if one of them faced a situation "that could create a threat to peace, disrupt peace or affect the security interests of either side".
Under the pact, Russia and Uzbekistan promised to provide each other with the right to use military installations on their territory.