Some 244,00 Scots fall into this category, new figures showed, with the number across the UK increasing by a million since the start of the economic downturn in 2008. A total of 3.05 million workers were under-employed, with almost two-thirds in part-time jobs, said the Office for National Statistics.
Occupations with the highest number of under-employed workers included cleaners, caterers and labourers.
The highest under-employment rates were in the East Midlands, Yorkshire and Humber, the north-east and the south-west, where more than 10% of workers wanted to work more hours. In Scotland, 9.9% of workers wanted to work more hours, which was the average amount for the UK.
A Department for Work and Pensions spokesman said: "Part-time working suits millions of people. For many it is an important step to full-time work."