The Cobblers, bottom of the Football League, parted company with Boothroyd on Saturday evening following their 4-1 defeat by Wycombe.
A statement on the League Two club's official website said: ``Northampton Town chairman David Cardoza has confirmed that Andy King, assisted by Tim Flowers, will take temporary charge of Northampton Town following the departure of Aidy Boothroyd.
``King, who was Boothroyd's assistant, will oversee the first team until further notice.``
Former Swindon manager King arrived at Sixfields alongside Boothroyd in November 2011.
In their first season in charge the pair guided Northampton to safety, having taken over with the club just above the League Two relegation zone.
Last season the former Watford, Colchester and Coventry boss led the Cobblers to the play-off final having finished sixth, before being beaten by Bradford 3-0 at Wembley.
However, during the current campaign Northampton have managed only four league wins and are three points from safety.