Just over half of women are saving adequately for their retirement compared with nearly two-thirds of men, a report has found.
Divorced and self-employed women are particularly likely to have a bleak outlook when it comes to their ability to save for the future, according to the research from Scottish Widows.
Some 52% of women generally were found to be saving adequately for their retirement, compared with 60% of men.
People were considered to be saving adequately if they were aged over 30 and putting at least 12% of their income away for retirement, including any employer contributions into a pension, or their main retirement income was expected to come from a "gold plated" defined benefits pension scheme, such as a final salary pension.
The retirement savings gap between men and women has widened compared with 2014, when 50% of women were saving adequately compared with 55% of men.
As well as continuing to lag behind men when it comes to retirement saving, there was some evidence to suggest that divorces are strongly hitting women's - and men's - abilities to save for their later years.
Seven in 10 (70%) divorced women believe they will be unlikely to save more in the next 12 months than they do now - a higher proportion than the 60% of women generally who said this.
Some 42% of divorced women were considered to be saving adequately, compared with 47% of divorced men, the Women and Retirement Report found.
Female entrepreneurs were also likely to be struggling to save. Just over a third (36%) of self-employed women were found to be saving adequately for retirement, compared with 47% of self-employed men and 58% of employed women.
Jackie Leiper, a retirement expert at Scottish Widows, said: "It is encouraging to see that over half of women are making sufficient savings towards their retirement, but a growing savings gap persists in the UK.
"It's vital that we address this to ensure women feel reassured about their finances and prepared for retirement, whether they are self-employed, work for a large employer, are divorced, married or single."
More than 5,100 people were questioned for the report.
A Department for Work and Pensions (DWP) spokesman said: "Automatic enrolment is helping millions of women to either start saving or save more for their retirement, and in 2014 there was no difference between men and women participating in workplace pensions."