ASDA said it would pay workers under the age of 18 at the same rate as adult staff following new EU rules on age discrimination.
Around 5,000 employees aged between 16 and 18 will see their pay increase from to 5.71 pounds an hour from 5.19 pounds, at a cost of 1.7 million pounds to the company.
Younger workers will see their take home pay rise by 300 pounds a year because of the increase, the first of its kind announced by a supermarket, ASDA said in a statement on Wednesday.
Worker and community rights have also become the latest front in the fight between Britain's largest supermarkets Tesco, ASDA and Sainsbury for shopper loyalty.
A European Union directive on age discrimination is coming in to force across member states by the end of the year.
The directive, adopted ahead of time this month, prohibits companies from forcing workers to retire at 65 years and allowing age to be a basis for recruitment.
Teenage pay is not included in the directive, but ASDA said the time was appropriate to reconsider the issue and that it was the first supermarket to adopt such a move.
With the new age discrimination rules coming into force, 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 groups, said Sarah Dickins, ASDA's head of reward and recognition.
It is common practice for retailers to pay workers under the age of 18 a lower rate of pay for doing the same job than someone older than 18.