Gorkss becomes Dean Saunders' first signing since he was appointed manager at Molineux a month ago and the deal is with a view to a permanent transfer at the end of the season.
"I am delighted we have brought Kaspars in," said Saunders on capturing the 31-year-old Latvia international.
"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.
"I think he can help take us where we want to go.
"He is strong, brave and no-nonsense and will put his head in - which is what we need. 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.
"This is a start for me of what I am trying to build here."
There is a 24-hour recall clause in the deal allowing Reading to bring Gorkss back to the Madejski Stadium after the first 28 days of the loan.