Obesity is a major cause of illness and death, and 10 types of cancer - including breast, bowel, womb and oesophageal - could be caused by being overweight.
But figures released by Cancer Research UK show that 74% of people are unaware of the link between obesity and the disease.
Their survey found that, as well as general ignorance about the connection, 77 per cent of those asked did not know that obesity was specifically linked to ovarian cancer.
Almost three quarters, 71 per cent did not know about the link with breast cancer and more than half, 53 per cent, were unaware that pancreatic cancer is connected to obesity.
There was better awareness of the link with bowel cancer, with three-fifths of Scots surveyed knowing about the association. Some 54% linked obesity with liver cancer.
More than a quarter, 28 per cent, of all adults in Scotland are estimated to be obese.
The charity said that being overweight or obese is the single biggest preventable cause of cancer after smoking and is linked to more than 18,000 cancer cases each year in the UK.
If the epidemic is not tackled there will be 670,000 additional cases of obesity-caused cancer in the UK over the next 20 years, which could cost the health service an extra £2.5 billion, the charity has warned.
Professor Linda Bauld, the charity’s expert in cancer prevention based at the University of Stirling, said: “Most people in Scotland don’t make the link between being overweight or obese as a risk factor for cancer and that’s worrying.
“Being overweight increases the risk of a number of cancers including some of the most common in Scotland like breast cancer.
“The Scottish Government needs to take responsibility for informing the public of the link and to take action to tackle the obesity epidemic. We know that an obesity strategy is currently being developed by them and we hope to see that published soon.
“It needs to include measures that protect children from junk food marketing and make it easier for families to buy healthy food. These measures could make a real difference, particularly to protect children’s health now and in the future.”
The YouGov survey for the charity took place from February 24 to March 8 and is based on a sample of 280 adults north of the border.