Williams, 31, was treated for a "chronic foot disorder," Dr. Jeffrey Rockefeller, a podiatrist, said.
The procedure was performed on both of Williams' big toes. Rockefeller said the operations were "minor" but Williams "needs to minimize activity to fully recover."
Williams, however, is expected to play in next month's Australian Open.
Williams was selected the WTA Player of the Year for 2012 after winning Wimbledon, the Olympics, the U.S. Open and the WTA Championships in the second half of the year.
The Australian Open is scheduled to begin Jan. 14.