The club announced the deal would keep McCulloch at Ibrox until 2015.
The 34-year-old has scored 14 goals this season after being handed a striking role and the captaincy at the beginning of Rangers' Third Division campaign.
McCulloch's previous contract expired at the end of this season and his new deal takes him to his 37th birthday.
If Rangers makes its way through the current Scottish Football League structure, the final season of his contract could be in the First Division.
The former Motherwell player joined Rangers from Wigan Athletic in July 2007 and has played in defence, midfield and attack.
Outgoing Manchester United chief executive David Gill expects Wayne Rooney to start the 2013-2014 season with the Premier League champion.