Remaining nine points adrift of Scottish Premiership leaders Celtic, Rangers have been keen to make first-team additions ahead of Tuesday's deadline.
Earlier this month, Todd Cantwell completed his switch from Norwich City to Ibrox, and it has now been confirmed that another midfielder has moved to last season's Europa League runners-up.
Rangers say that Raskin has been signed for an undisclosed fee on what they describe as a 'long-term contract'.
The Belgium Under-21 international has earned his move to Rangers through emerging as an influential figure in his homeland with Standard Liege.
A total of five goals and 13 assists have been contributed during 96 appearances in all competitions, and he has featured heavily in helping Liege occupy sixth spot in the top flight during 2022-23.
Speaking on the move, Raskin told the club's official website: "I feel very excited to be here and I also feel very proud to join a very big club.
"I'm looking forward to playing at Ibrox. It was very exciting when I was told of Rangers' interest because it's a big club.
"I'm looking forward to making my debut and I hope it can be as soon as possible."
Head coach Michael Beale added: "As a football club, Nicolas is a player that we have tracked for a long time and we are very pleased to welcome him and his family to Rangers.
"He is a young player that has already amassed good experience both in domestic and European competition. I am looking forward to working with him closely and integrating him into our team."
As a result of not yet receiving his work permit, Raskin will not be in contention to feature against Hearts on Wednesday evening.