The Alberta government will bring in legislation this session to recognize the validity of same-sex marriages.
"I think it's an important step forward," said Sandra Jansen, associate minister for family and community safety, who is introducing the amendments. "It's a simple housekeeping process. It moves us to where we need to be, aligned with the federal government.
"It's a good day for us."
The legislation will change the preamble to the Marriage Act that currently defines marriage as an institution between a man and a woman.
The changes were approved by the Progressive Conservative caucus.
Alberta's Marriage Act preamble, passed in 2000, has never been updated even though the federal government made same-sex marriages legal in 2005.
The decision comes days after some Progressive Conservatives and the Wildrose party were criticized for joining forces to defeat a non-binding motion to urge schools to bring in gay-straight alliances.
The changes will be introduced in the spring session, interim premier Dave Hancock said.
All opposition parties are indicating they will vote for the amendments.