Al Wefaq leader Shaikh Ali Salman has been given four-years jail term for spreading sectarian hate and insulting government body.
He was found guilty of inciting hatred against a certain sect, insulting the interior ministry and inciting others to break the law on Tuesday, Gulf Daily News reported.
However, the High Criminal Court acquitted him of seeking to change Bahrain's political regime by force due to lack of evidence.
He was handed a two-year jail sentence for inciting others to break the law, and 12 months each for the other two charges.
According to investigations by prosecutors, during 2013 and 2014, he incited hatred against naturalised Bahrainis during speeches he gave in ma'tams and mosques.
He labelled them as mercenaries and said they were repressing original Bahrainis, saying that they can booby-trap vehicles and be suicide bombers.
"The defendant also labelled policemen as mercenaries saying they belonged to terrorists groups."
In several speeches, he incited violence against policemen, criticised the government for alleged "political naturalisation" to change the country's demographics, and incited people to forcibly take to the streets in Manama.
Shaikh Salman, who earlier denied all charges, was arrested on December 28 and has already spent more than five months in police custody.
His sentencing has been criticised by is party.