Premier League clubs have been urged to pay all staff above minimum wage rates after spending £1.41bn on players.
Many cleaners, security guards, caterers and other staff do not earn enough money to cover the cost of living, the charity Citizens UK said.
It said only four out of 20 Premier League clubs are accredited by the Living Wage Foundation.
The clubs who have not signed up have been accused of losing touch with "the lives and struggles of workers".
Companies accredited by the Living Wage Foundation commit to paying all staff and any third-party contract workers the "real living wage" - a voluntary rate of £9 an hour and £10.55 in London that is higher than the statutory UK National Minimum Wage and National Living Wage of £8.21.
Everton, Liverpool, Chelsea and West Ham have all made the pledge - while some football clubs outside the top league, such as Championship side Luton, also pay the voluntary rate.
Another Premier League side, Brighton & Hove Albion, are not accredited by the Living Wage Foundation but say they have been paying the "real living wage" rate for a number of years.
"I struggle to put food on the table for my family and I often have to have cut-price meals," said a cleaner who works at Manchester United's Old Trafford stadium.
"Considering the amount of money in football, it would be great to see the club paying all their staff a fair and decent wage," he said.
Premier League clubs made a record combined revenue of £4.8bn in the 2017-18 season.
By the end of transfer deadline day on Thursday the top clubs in English football had spent £1.41bn in a summer of signing new players - just short of the £1.43bn record set in 2017.
Citizens UK said a new football season was starting with employees "left on the breadline" which was "not right when clubs are splashing out record fees on players".
Update 9th October 2019: This story has been updated to clarify that Brighton & Hove Albion were also paying staff at the "real living wage" rate and in September 2019 were accredited by a scheme administered by Brighton Chamber.