The West London club have been searching for a new manager after sacking Gareth Ainsworth following Saturday's 2-1 defeat to league leaders Leicester City.
The result represented a sixth consecutive defeat and left QPR languishing in 23rd position with eight points to their name after 14 games.
The appointment of Cifuentes is subject to a work permit and will result in the Spaniard leaving his position at Swedish top-flight club Hammarby.
Cifuentes took charge of his final game as Hammarby boss on Monday evening, seeing his side concede two stoppage-time goals to draw 2-2 with Sirius.
The 41-year-old, who has been with the Swedish side since January 2022, leaves the club in sixth position with two games remaining in the season.
QPR CEO Lee Hoos told the club's official website: "We are delighted to bring Marti in and I would firstly like to thank Hammarby for being fantastic to deal with throughout the process.
"Marti is an exciting appointment and we look forward to seeing the impact he can have. Having a succession plan in place is a necessary part of football, irrespective of how the team are performing.
"Martí is someone we have been aware of so we are really pleased to have been able to secure his services."
Despite being a relatively young manager, Cifuentes boasts almost a decade of coaching experience after beginning his journey in senior management with Spanish side UE Sant Andreu in 2014.
Cifuentes went on to manage CE L'Hospitalet, before leaving his home country to take over the position as Sandefjord boss in Norway.
After over two years coaching Sandefjord, Cifuentes reached an agreement to become the new manager of Danish side Aalborg, where he spent 12 months before departing for Hammarby.
In his first season with the Swedish side, he led them to a Svenska Cupen final and a third-place finish, securing the club a place in the qualifying stages of the Europa Conference League.
While he has been unable to replicate that success this term, Cifuentes's coaching credentials have caught the attention of the QPR hierachy.
Cifuentes will travel to London on Tuesday, before he takes charge of his first game against relegation rivals Rotherham United on Saturday.