The supermarket group said that the move would cost it £1.7m, with each of its 5,000 workers under the age of 18 taking home an extra £300 a year.
Sarah Dickens, head of reward and recognition at Asda, said: “We simply don't see why young people under the age of 18 working in our stores should be paid any less for doing the same job as someone a bit older.”
She added: “With the new age discrimination rules coming into force next week, we've taken another look at all our policies and have decided we no longer think it's acceptable to have different pay rates for different age groups.”
The GMB union welcomed the move. GMB national officer Jude Brimble, said: “This is a very important breakthrough at Asda for young workers. GMB welcomes this and considers that the Low Pay Commission should follow suit and recommend that this becomes the law of the land.”