Abdallah Ja’far al-Ojami, 18, was shot dead by security forces near a police station on Friday as the protesters were demanding the immediate release of prominent Shia cleric Sheikh Nemr al-Nemr
Al-Ojami was the latest victim of Saudi police crackdown on protesters.
Tension has been high in the province since Nemr's detention last week with almost daily protest rallies in the oil-rich region.
At least three people have been killed and many others injured in the crackdown on demonstrations against the detention of the cleric.
The Eastern Province has been the epicenter of anti-regime protests since last year. Saudi protesters demand the release of all political prisoners, freedom of expression and assembly, and an end to economic and religious discrimination against the eastern region.
The demonstrations, however, have turned into calls for the downfall of the Al Saud regime. The calls were further fueled by the November 2011 killing of peaceful protesters in the troubled region.
Anti-regime protests continue in the ultra-conservative monarchy, where any demonstrations or political gatherings are strongly prohibited and met with repressive force.