Iyad Qunaibi, a Jordanian born in Kuwait in 1975, was arrested in mid-June for posting on his Facebook page an audio message entitled "Jordan on the brink of the abyss" critical of government policies.
In it, he criticised Jordanian relations with Israel - the two neighbours are bound by a peace treaty - and slammed the "Westernisation" of Jordanian society.
Qunaibi's lawyer said the sentence - delivered by the state security court, a military tribunal - was harsh and "unexpected" and that he would appeal.