Women are typically putting away around £1000 less a year than men as they increasingly see saving for retire-ment as a "luxury" they can't afford.
Women in their twenties have been singled out by the study as they are dealing with short-term financial pressures, such as holidays, paying off debt or saving to buy a home, rather than making proper retirement provision.
It comes amid the looming threat of a pensions time bomb. The IMF recently warned that increases in life expectancy could impose a financial burden of up to £750 million on public services in Western economies such as Britain.
Martin Potter, a partner at Glasgow-based company pensions advisers Hymans Robertson, said women tend to work more part-time hours than men and earn less than men in the same job.
He pointed to the abolition of final salary pension schemes by most firms, adding: "We've seen such a squeeze in household incomes recently that I wouldn't be surprised if we look back on saving for pensions during these last few years as a luxury that a lot of people simply couldn't afford."
The picture emerged in the annual Scottish Widows Women and Pensions Report, which has been tracking the figures since 2006. It also revealed that just 49% of men are saving enough.
Women are on average putting £2184 away per year into a pension pot while men are saving £3120.
The proportion of women found to be saving adequately peaked at 50% two years ago, while for men a high of 54% put enough money aside in 2009, just after the recession began.
Mr Potter added: "For a lot of people it's just too late now and they are relying on the state pension, but the problem is we just don't know that's even going to be there by the time they reach retirement age."
Stuart Faloon, principal for Scotland at pension experts Mercer Consulting, said the difficulty in providing adequately for retirement could have been driven by the high costs of annuities.
Mr Faloon said: "Interest rates have been so low in the last few years that the amount of pension that can be bought with a lump sum has been in decline.
"In the last two to three years annuity prices have been at their most expensive level ever, and poor gilt yields and continuing improvements for life expectancy haven't helped.
"Men are not much better. The general theme over the last few years has been with less income being squeezed - the freeze on pay rises, cost of living going up so much - that people don't have the surplus income to put aside."
The report urged politicians and the industry to "work harder" to understand the obstacles to building a retirement pot faced by women, who are often forced to prioritise more immediate family needs over long- term saving.
It also uncovered a black hole where around one-fifth of women, mainly those in their 40s, were relying on their partner's pension to support them in later life.
However, these women are often unclear how their partner's savings and their own would be divided if they broke up.
The report revealed that more than half (54%) of 22 to 29-year-olds don't have a pension, compared to 37% of the general female population.
Meanwhile, only 50% of women in their 30s work full-time compared to 81% of men of the same age, resulting in an average earnings gap of almost £10,000.
Lynn Graves, head of business development, corporate pensions at Scottish Widows, said the report was worrying and warned that women have to act now to ensure they are not exposed to financial problems in later life.