The court's ruling was in response to two cases: one request was filed by veteran gay rights activist, Chi Chia-wei, the other by Taipei city officials.
Announcing the result of a two-month-long constitutional review on Wednesday afternoon, the panel of 14 judges ordered the legislature to either amend the Civil Code or introduce new provisions to recognise same-sex marriage within two years.
According to reports, the public opinion in Taiwan had always largely supported the legalization of same-sex marriage - especially with a recent string of successful Gay Pride marches, each of which have drawn attendance from tens of thousands of people.
Ahead of today's ruling, there were signs that Taiwan was poised to legalize same-sex marriage. The ruling from the Constitutional Court Republic of China will now be sent to the parliament, or Legislative Yuan, who will be tasked with amending marriage laws.
Draft legislation is already making its way through Taiwan's Parliament but it has stalled.
The court also explains its reasons behind ruling in the release, saying that disallowing two persons of the same sex to marry is a "different treatment" with "no rational basis" either for the sake of "safeguarding basic ethical orders" or "their inability to reproduce".
Past attempts to legalise same-sex marriage stalled under the Kuomintang, which dominated politics for decades until it was unseated by President Tsai Ing-wen's Democratic Progressive Party previous year. Before she was elected previous year, she publicly declared her support, saying, "in the face of love, everyone is equal". "Family conflicts will increase and the whole definition of marriage will be changed", said Andrew Chang, a spokesman for an anti-gay marriage group Alliance of Religious Groups for the Love of Families Taiwan. The ruling on Wednesday comes as the gay community is reported to be facing increasing persecution in the country. A new law could recognize unions between same-sex partners but be limited in scope. "They say it's time for all Taiwanese people to have their say in this debate, and claim a cultural convention is under attack".
"Amnesty International activists across the world will continue to urge Taiwan's government to say yes to equality".