The UAE State Security Court jailed 56 of the 94 Emiratis for between seven and 10 years while jail terms of 15 years were handed down to eight tried in absentia, the state-run news agency WAM reported.
Five have been handed sentences between three to seven years. Another 25 people, including 13 women, were acquitted.
The verdicts cannot be appealed, and those found guilty will begin serving their sentences immediately, including time already served, the Ministry of Justice said in a statement.
The convicted were members of now-disbanded Al Islah Society, an Emirati-based Islamist group linked to the Muslim Brotherhood.
During the hearings, the public prosecution had called on the court of justice Falah Al Hajiri to apply the maximum sentence of 15 years against the defendants.
The prosecution had argued that the main goals of the organisation "was to infiltrate the country's educational and social institutions" and "seeking to oppose the basic principles of the UAE system of governance and to seize power".
The convictions were condemned by Human Rights Watch.
Nick McGeehan, the organisation's Gulf researcher, said they represented "another low point for the UAE's worsening human rights record".
"These verdicts cement the UAE's reputation as a serious abuser of basic human rights," McGeehan was quoted as saying by BBC.