The Ligier JS25 was a Formula One car designed by Michel Beaujon and Claude Galopin for use by the Ligier team during the 1985 Formula One season. Like its predecessor, the JS23, the JS25 was powered by a turbocharged Renault V6 engine although the car ran on Pirelli instead of Michelin tyres. Drivers of the car were initially Andrea de Cesaris and veteran Jacques Laffite but after a series of crashes, de Cesaris was replaced in the team by Philippe Streiff.
Using the JS25, the French team were able to score 23 points in 1985 and finished 6th in the Constructors Championship. Laffite was able to score two 3rd place finishes and also a 2nd place at the season ending Australian Grand Prix where team mate Streiff also managed to finish 3rd, although his efforts to take 2nd from Laffite almost cause both cars to not finish the race. Streiff made contact with Laffite on the penultimate lap of the race and drove the last with his left front wheel almost off the car.
Perhaps the most spectacular moment for the JS25 came at the Austrian Grand Prix when de Cesaris destroyed his car in a high speed rollover on lap 14. It was after this event that team owner Guy Ligier decided he could no longer afford the repair bills for de Cesaris's frequent crashes. He was replaced by Streiff after the Dutch Grand Prix.
The JS25 was replaced for the 1986 season by the Ligier JS27.