Ahmad Shabaneh, the reported ringleader, was handed a 10-year jail sentence, although the prosecutors had demanded the death penalty against him and his co-defendants, three of whom remain on the run.
Fugitives Ahmad Yassin and Haitham al-Gazzaz were also given 10-year jail terms, while the other defendants were sentenced to between two and seven years in prison.
Following the verdict the convicted men, who sat chained in the dock in a metal cage, shouted "you are the enemy and a tyrant, we are all fighters for God and Islam's victory" at the judge, the AP news agency reported.
The court found that Shabaneh had formed a group called Al-Taa'efa al-Mansourah, or the Victorious Sect, in 2003 which planned to attack US soldiers engaged in training Iraqi police recruits at a desert camp in Jordan.
It also plotted to send fighters to Iraq to attack US forces and planned attacks against Americans and Israelis in Jordan, court documents said.
The court said it handed down lighter sentences to give the suspects a chance to improve themselves, although the charge of conspiracy to carry out attacks carried the death sentence.
Defence lawyers said they will appeal the verdicts.
The prosecution did not say if the group was linked to the al-Qaeda network, however the indictment alleged that Shabaneh had been influenced by the ideology of Abu Musab al-Zarqawi - the Jordanian-born leader of al-Qaeda in Iraq who was killed by a US airstrike in Iraq in June.
The indictment said that Shabaneh had distributed leaflets and computer discs bearing quotations of al-Zarqawi at mosques in Jordan.