Parliament speaker Khalifa al-Dhahrani said 31 MPs out of the 40-member chamber voted to eject Osama Mehanna, in a statement published by BNA state news agency.
Dhahrani did not disclose the reason behind his removal.
But political sources pointed out that Mehanna had a fierce argument with fellow MPs on April 29 after he criticised the situation at Jaw Prison, in southeastern Bahrain.
Mehanna was elected in October 2011 in partial polls held to replace 18 MPs of the Shiite Al-Wefaq opposition group who resigned in protest at violence used to quell a month of pro-reform protests.
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The Sunni-ruled kingdom has been widely criticised by rights groups over its crackdown on the protests led by the Shiite majority, and for the alleged mistreatment of detainees.
Amnesty International yesterday voiced concerns over the "continuing detention of prisoners of conscience and the harsh sentences handed by Bahraini courts in connection with rioting, including against children."
The watchdog said, however, that it "found encouraging government openness during discussions on human rights," as an Amnesty delegation was allowed to visit the country for the first time since January 2013.
Bahrain, home to the US Navy's Fifth Fleet, remains deeply divided three years after the quashed uprising, with persistent protests sparking clashes with police, scores of Shiites jailed on "terror" charges and reconciliation talks deadlocked.