It says that, on average, women have £7,500 in defined contribution pension schemes, compared with £14,500 for men, reports the BBC.
The smaller the amount saved in a pension pot, the smaller the income that can be drawn from it.
In defined benefit- otherwise known as final salary – schemes, women typically have £32,000 in savings, while men have £62,900.
The study, carried out by the Pensions Policy Institute (PPI), says women receive smaller state pensions too.
It says that female pensioners receive 25 per cent less than men, which amounts to £2,548 a year.
The report, called Under-pensioned 2016, also notes that carers, black and Asian workers and the self-employed have smaller than average pensions.
“Women, carers and ethnic minority workers will continue to have a tough time in old age if swift action is not taken,” said Frances O’Grady, the TUC’s general secretary.
“We urgently need a debate on how unions, government and employers can work together to can build on the success of auto-enrolment.”
Previous research by the government has shown that women are more likely than men to opt out of auto-enrolment schemes, but that may be because a greater proportion of them work part-time.
A two-year study into the future of pensions commissioned by the Labour party is due to be published on Wednesday.
