Tesco said it would be reducing the cost of its petrol by up to 3p a litre from today.
It was followed swiftly by Asda, which said it was cutting its petrol by 2p a litre, with the reduction also taking effect from the same time.
Asda said its new pricing would mean motorists would pay no more than 129.7p a litre for petrol, with diesel costing 137.7p.
RAC technical director David Bizley said: "Every penny off fuel makes a difference for motorists.
"This will help make it a little more affordable for families to travel to spend time together this Christmas."