The most immediate repercussions were felt by the airborne forces and 21st Army Group. British 1st Airborne Division was disbanded, having lost almost 3/4s of it's strength at Arnhem, while the American Airborne divisions endured heavy fighting in the Njimegen Salient that the operation created. It was especially bad for Maxwell Taylor's 101st, defending 'Hell's Highway'. XXX Corps found itself occupying a precarious salient, over which much fighting would take place into 1945, and the Arnhem bridge was bombed shortly after the operation failed. For Canadian 1st Army, it meant more bloody, drawn out fighting for the Scheldt Estuary, an objective that should have taken priority over Market Garden.
In the long run, it meant that until Antwerp could be opened, and more supplies to be accumulated from the ports that were available, Allied operations would have to be scaled down, to a degree. 1st and 9th US Armies continued to batter the German positions south of the Reichswald, enduring heavy losses in the Hurtgen Forest. Patton found himself in a similar situation around Metz and Fort Driant, while the Franco-American US 6th Army Group sought to cross the Moselle and penetrate the Saverne Gap, so as to advance into Alsace-Lorraine. By November 1944 this had been achieved, and the German 1st and 19th Armies suffered heavy losses in mobile fighting, the former driven into the Saarland, the latter holding onto the Colmar Pocket, a small sliver of Alsace.
For the Germans, the victory in Market Garden meant that more time was gained to build up their defences, the old Siegfried Line and the new West Wall, and as of September 1944 preliminary planning began for an offensive in the West, with the Ardennes ultimately being decided upon as the area of operations.