The tribunal's decision sent a message that the Sunni monarchy is not easing off on punishments linked to the unrest despite appeals for talks with Shiite groups in the strategic Gulf island kingdom, which is home to the US Navy's 5th Fleet.
Shiites account for about 70 per cent of Bahrain's population but claim they face widespread discrimination such as being blocked from holding top military or government posts.
Shiite leaders have called on authorities to end security crackdowns and trials before considering talks with the Sunni ruling family.
The official Bahrain News Agency said Ayat al-Qurmezi was convicted of anti-state charges, including inciting hatred. She can appeal.
Al-Qurmezi read the poems critical of Bahrain's king and prime minister after demonstrations inspired by the revolts in Tunisia and Egypt broke out in February.
Two former parliament members, Jawad Fairooz and Mattar Mattar, also went on trial as part of wide-ranging arrests and trials of perceived enemies of the ruling system. Both are members of the main Shiite political group, Wefaq, whose 18 lawmakers resigned to protest the harsh measures against protesters.
At least 31 people have been killed in the unrest in Bahrain.
The US and the EU have condemned the violence, but have stopped short of any tangible punishments against the rulers of the traditional Western ally in the Gulf region.