Under the terms of the deal, Championship side Wolves have the option to make the move a permanent one during the summer.
"I am delighted we have brought Kaspars in," manager Dean Saunders told the club's official website.
"He has been with teams who have been promoted from the Championship over the last two years and is 31 which is a good age for a central defender.
"He also has a good character and is a winner, and that can only help the group. He is an experienced player who has played in the Premier League this season and also played for his country last Wednesday night."
The Latvian international has become Saunders's first senior addition at Molineux.