The decision comes in the wake of a drawn-out scandal involving Park Geun Hye's friend and confidante Choi Soon Sil. The Constitutional Court now has up to 180 days to decide whether to formally end her presidency.
In South Korea's 300-member parliament, 234 lawmakers voted to impeach President Park Geun Hye on Friday, including some members of her own party.
With an approval rating of only 5 percent - the lowest among South Korean leaders since democracy arrived in the late 1980s - her position had become untenable.
Some 160 MPs affiliated with the two main opposition parties had said they would resign en masse if parliament did not approve Park's impeachment.
Prosecutors have alleged collusion with a longtime friend to extort money from companies and giving the confidante undue influence over government decisions.
Park - whose term was to end in early 2018 - has publicly apologized over the scandal and admitted she had received help from Choi in editing her speeches and with unspecified "PR" matters, but denied involvement in Choi's alleged criminal activities.
She also said she would stand down if parliament arranged a stable transfer of power.
Protesters carry torches as they march toward the presidential Blue House during a rally against South Korea's President Park Geun-Hye in central Seoul
Anti-Park protests continue
Hundreds of protesters rallied overnight in front of the National Assembly's main gate.
A group of anti-Park farmers who tried to drive into the capital on tractors and trucks had skirmishes with police overnight in Suwon, just south of the capital, Seoul.
Most reportedly then left their vehicles behind and headed to Seoul on buses.
The country's Constitutional Court now has up to 180 days to determine whether to formally end Park's presidency.
Park will be suspended as president during this period but not removed, with her duties, including commander in chief of South Korea's 630,000-member military, temporarily transferred to Prime Minister Hwang Kyo-Ahn.
South Korea's financial minister, Yoo Il-ho, has called an emergency meeting for later on Friday to discuss the implications of Park's impeachement.
Park - the daughter of a military dictator still revered by many conservatives - has immunity from prosecution while in office.
Choi Soon-sil - a daughter of Choi Tae-min, who served as a mentor to Park's father Park Geun-hye until his death in 1994 - and two former presidential aides allegedly linked to the scandal have been indicted.
jbh/kms (dpa, AP, Reuters, AFP)