US researchers, who looked at a poll of 340,000 people, found moods were no worse on Mondays than other working days, except for Friday.
The popular fixation on the idea of "Blue Monday" should be given the status of a "cultural myth", the team behind the new findings wrote in the Journal of Positive Psychology.
People were happier as they approached the weekend, lending support for the concept of "that Friday feeling".
The report authors told the Journal of Positive Psychology that the concept of miserable Mondays should be ditched.
"Despite our global beliefs about lousy Mondays, we conclude that this belief should be abandoned. Cultural myths may vastly over-emphasise actual day of the week mood patterns," the 'BBC News' quoted Prof Arthur Stone of Stony Brook University as saying.
Similarly, claims that the Monday of the last full week of January - dubbed "blue Monday" - is the most depressing of the whole year have been debunked by others.
Prof Stone's team analysed data collected by Gallup from telephone interviews.
Half the respondents were male and half female and they represented all ages from 18 upwards with an average age of 53.
The researchers, however, found evidence for a 'Thank God it's Friday' effect, making people's moods on the final week day significantly better than earlier in the week.
People reported more enjoyment and happiness and less stress or worry on Fridays, Saturdays and Sundays compared with the rest of the week.
Stone says it is the contrast in mood from Sunday to Monday that has led to Mondays being unfairly singled out.