Sheikh Salman was convicted of inciting hatred, promoting disobedience and “insulting” public institutions.
His al-Wefaq movement has accused the Sunni-led government of aggravating the country’s crisis with his sentencing.
Sheikh Ali Salman jailed.
The Gulf state has grappled with sporadic unrest since putting down mass Shia-led protests in 2011.
Sheikh Salman’s arrest in December triggered protests across the country.
“The regime is pushing toward aggravation and issued a sentence of four years for the Bahraini opposition leader Sheikh Ali Salman,” al-Wefaq tweeted.
Bahrain’s state news agency BNA said Sheikh Salman had been found guilty of charges “relating to publicly inciting hatred, an act which disturbed public peace, inciting non-compliance with the law and insulting public institutions”.
But he was acquitted of inciting political change by force, for which he could have been jailed for life.
The charges relate to a series of statements by Sheikh Salman made in a public speech last year.
His defence lawyer, Abdullah al-Shamlawi, has said that Sheikh Salman can appeal Tuesday’s verdict.
Shia-dominated demonstrations against the Sunni monarchy have been continuing sporadically for the past four years.
In 2011, dozens died when the government moved to quash protests. The demonstrators were demanding more rights and an end to discrimination against the majority Shia community by the Sunni royal family.