"The Constitutional Court nullified with a decision on December 4, 2017 the legal regulation that until now prevented such couples from marrying," a statement said.
It said that this would come into force on December 31, 2018.
The ruling came after a case was brought by two women in a registered civil partnership who were denied the right to marry by authorities in the capital Vienna.
In April 2001 the Netherlands became the first country in the world to allow gay and lesbian couples to marry in a civil ceremony.
Many eastern European countries -- including Bulgaria, Latvia, Lithuania, Poland, Romania and Slovakia -- deny homosexuals the right to marry or enter into unions.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)