Emma Raikes was travelling to Disney World in Florida with her two-year-old niece, her mum and other members of their family on Monday morning and had paid extra to enter the lounge before their flight.
But when she tried to get into the Aspire Lounge at Manchester Airport on Monday morning, staff turned her family away.
They have used it on previous trips - and Emma's mum Jane Walshaw had forked out almost £700 for the privilege ahead of their 'family moon', the Manchester Evening News reports.
Even Emma's two-year-old niece had to cover her t-shirt up with a jumper
Emma said the family were very disappointed
Emma said they were turned away from the lounge because of their Minnie Mouse tops - which had their names on - and were only allowed in when they agreed to wear jumpers.
Swissport, which owns and operates the lounge, apologised and said staff could be 're-educated' on dress code rules.
Emma said: "We were extremely disappointed at the hassle we faced when trying to enter the lounge we had booked.
Emma's tweet about the lounge
"We are on a family moon to Disney and did not think a Minnie Mouse t-shirt with our name on would be seen as offensive. It was a disappointing start to our holiday.
"I wouldn't mind but a Minnie Mouse t-shirt with our name on is not offensive in any way.
"My niece was grumpy and crying as she was hungry.
"It's not like we were a stag or hen party."
She added: "They eventually let us in, but only if we put jumpers on. We were boiling and the lady on the desk wasn't even nice about it.
"We have been in the escape lounge twice before which is lovely and never had any issues."
The family were denied entry to the Aspire Lounge
A spokesman said: "Our lounges do have a dress code in which we allow guests to wear a myriad of smart casual items and disallow other items such as tour shirts, sportswear and fancy dress.
"On this specific occasion, the member of staff who dealt with the family was wrong to have asked them to cover their personalised t-shirts and has misinterpreted the dress code, which is designed to ensure a comfortable atmosphere for all guests within our network of lounges.
"We sincerely apologise to the family for this genuine mistake and would encourage them to contact us directly to resolve this matter.
"The entire team at Manchester Aspire Lounge will be re-educated on the dress code to ensure this does not happen again."