Archibald has agreed a one-year rolling contract, with Scott Paterson appointed as his assistant.
Former Jags defender Archie was named as interim boss after Jackie McNamara left to join Dundee United in January, and has won five and drawn one of his six matches at the helm, keeping the club two points behind Irn-Bru First Division leaders Morton with two games in hand.
Club chairman David Beattie said: "I'm absolutely delighted to be able to confirm the appointment of Alan Archibald as Partick Thistle manager and Scott Paterson as his assistant.
"I look forward to working closely with them as we continue to work hard at providing a club that we can all take pride in."
Thistle are at home to Livingston tomorrow as they continue their bid to win promotion to the Premier Division.