Workers at 1,500 companies are set to benefit as the London Living Wage increases to £10.20 an hour.
The so-called "real living wage" rose by 45p an hour, or 4.6%, for workers in the capital.
Monday's announcement came as the Living Wage Foundation (LWF) hiked the UK Living Wage by 30p an hour to £8.75.
Higher inflation, rising housing rents and transport costs are the driving factors behind the move.
The LWF said the hike would give "relief" to workers battling stagnant wages.
The announcement follows new research by KPMG showing that 5.5 million people across the UK, or 21% of the workforce, are still paid less than the voluntary rates.
Heathrow, which is among over 150 employers to agree recently to pay the higher rate, said 3,200 airport workers will be paid the voluntary living wage by 2020.
LWF director Katherine Chapman said: "The new rates will bring relief for thousands of UK workers being squeezed by stagnant wages and rising inflation.
"It's thanks to the leadership of over 3,600 employers across the UK who are committed to paying all their staff, including cleaners and security staff, a real living wage.
"Great businesses know that, even during these tough times, not only is fair pay the right thing to do but paying the real living wage brings big benefits."
Sadiq Khan said he was "pleased" with the development.
"I am determined to make London a fairer and more equal city, and the news that more 1,500 businesses are paying the wage is a good step towards achieving that," he said.
"But we need to go further - and for many more businesses and organisations to sign up."