The Light Blues hierarchy fined both players for their part in an incident that took place in the aftermath of a 4-0 Scottish Cup defeat at the hands of Celtic in April.
Then club captain Wallace was fined four weeks’ wages - the maximum penalty - after the alleged dressing room bust-up at Hampden Park, with Miller told to pay back half of his final Rangers wage packet.
Wallace, who was out injured, was accused of an angry outburst at former manager Graeme Murty, with Miller - an unused substitute - reportedly heavily reprimanded after launching a stinging criticism of Murty’s approach to the game.
Club chiefs felt the duo had gone too far and, following negotiations with managing director Stewart Robertson and the Gers’ human resources department, made the decision to suspend both players on full pay.
However, both Miller and Wallace denied that the bust-up had taken place, and went straight to the SPFL to contest the punishment.
On Wednesday, the league’s governing body upheld the duo’s appeal following close to a month of deliberation.
A statement from Rangers read: “The club is surprised by the decision of the SPFL’s Tribunal on this matter and disappointed that the decision seems to have been leaked before the club were advised of it by the SPFL.
“Decisions on such matters deal largely with procedural issues, not the conduct which gave rise to the club’s sanctions.
“The club was only presented with a 40-plus page decision after 4 o’clock this afternoon and will now take some time to consider matters before deciding how to proceed.”
Wallace has been handed a reprieve under new manager Steven Gerrard, although the former Hearts defender has lost the Ibrox captaincy to fellow defender James Tavernier, and was omitted from the club’s Europa League squad.
He is now in the final year of his contract.
Miller left Rangers during the summer, and was appointed player-manager of Livingston.
However, the ex-Celtic and Hibs forward left his post just weeks later after a disagreement over his role, and signed a two-year deal with Dundee as a player.