Almost one in five of those aged 55 and over say their biggest financial regret is not starting to save for their retirement sooner.
Other money regrets included running up debt on credit or store cards, not sticking to a budget and investing in stocks and shares, according to Standard Life.
Running up debt on credit and store cards was the number one regret among other age groups, with this affecting 21% of 35 to 44-year-olds.
Meanwhile, one in seven of 18 to 24-year-olds cited both running up credit and store card debt and wishing they'd spent less on nights out as their biggest financial mistake.
On a positive note, the research showed one in 10 said they intend to invest into their personal pension this tax year, and one in five plan to save into their workplace pension.
Those in the 25 to 34-year-old age group appear the most eager to invest for their future – one in six is planning to save more into their personal pension this year than last.
Standard Life's Julie Hutchison commented: "This new research should come as a wake-up call to the many people who aren't saving enough for when they retire. The value in starting to save early is clear in terms of increased potential for growth.
"We also know from previous research that parents often find they need to de-prioritise their own saving when they are older, to help support their adult children with large expenditure such as university fees and deposits for their first homes. So trying to close up a savings gap later on in life can be really tricky. We should all learn from the experience of baby boomers and start saving as soon as we're able to, so we don't share the same regret when we're older."