The airline has apologised for "causing inconvenience" to the group travelling with the Share A Dream Foundation.
The brave children, who have life-threatening conditions, were recipients of National Children of Courage awards at the weekend and were on a trip to Disneyland Paris.
However their dream holiday got off to a bad start as they prepared to depart Dublin Airport yesterday.
Several families were told their checked-in luggage -- containing the children's medicines and other important items -- exceeded weight limits. The families said they were annoyed and humiliated after they were forced to unpack some of their bags and repack belongings in others.
One parent told how their suitcase was 6kg over the 15kg limit and they were facing a €120 excess fee. Fortunately two other parents stepped in and offered to take items, including medicines, in their luggage.
The Share A Dream Foundation branded the incident a "disgrace".
However Ryanair said the families were given the opportunity to repack their bags so that they could avoid paying excess baggage fees.
"We sincerely regret any inconvenience, but are pleased that they avoided any excess bag charges.
"These families agreed to Ryanair's (very well known) checked in baggage policy (one checked in bag per person of no more than 15kgs in weight) at the time of their original booking.
"As their checked-in bags ...were overweight they were offered the opportunity to repack their bags rather than pay an excess baggage fee. As a result these families avoided any excess bag fees," said Ryanair.
Eight children received National Children of Courage awards.
Among them were six-year-old Sophie Mulcahy from Rhebogue Road in Limerick who suffers from the rare Ohdo Syndrome and has undergone six heart operations. Also honoured was Caitlin Doyle, also six, from Enniscorthy, Co Wexford, who has leukaemia.
Another winner was Ben Kelly (9) from Gorey, Co Wexford, who has undergone two kidney transplants in the past two months.
Guests who attended the awards ball helped pay for the children and their families to go to Disneyland.