Primark, part of the Associated British Foods conglomerate, said retail workers will be paid a minimum of £11 ($13.59) an hour, or £11.51 an hour in London.
The UK government-mandated National Living Wage will rise to £10.42 an hour from April, an increase of 9.7%.
With UK inflation rising to 10.4% in February, the Bank of England is watching pay settlements closely as it weighs any further rises in interest rates.
Primark's UK retail director Kari Rodgers said the latest rise "reflects our commitment to continue to invest in our people and our stores as we continue to grow.”
The retailer plans to invest £140 million in the UK high street over the next two years, including the opening of at least four new stores.
Last month, AB Foods raised its financial guidance for full year 2022-23, saying consumer spending had proven to be more resilient than it expected.
At the time, the company forecast first-half sales and adjusted operating profit 'strongly ahead' of the previous year and ahead of pre-COVID 19 levels, reflecting an improved performance from its Primark fashion business.
Grocery price inflation in the UK hit 17.5% over the four weeks to 19 March, new data from Kantar has shown, with take-home grocery sales rising by 8.6% over the most recent 12-week period.