Thomas Cook said it has donated £1.5m (€2.07m, $2.35m) to charity from the compensation payout it received after two British children died from carbon monoxide poisoning while staying at a Corfu hotel.
The firm was heavily criticised last week when it received £3 million in damages in connection with the deaths of Bobby, 6, and Christi Shepherd, 7, when their parents, Neil Shepherd and Sharon Wood, were only awarded £350,000.
The children died after breathing in carbon monoxide fumes while sleeping at the Louis Corcyra Beach Hotel on the Greek holiday island in 2006.
An inquest jury ruled they had been unlawfully killed and said Thomas Cook "breached its duty of care".
The firm said it was not making a comment about the UNICEF donation, BBC reported.
Tensions between Thomas Cook and the couple escalated when the firm issued a public apology over their compensation amount to the media before them.
A statement released by the couple, who are now divorced, said: "It is disgraceful that after all we've been through Thomas Cook are still putting us last in the equation.
"We haven't had this 'so called' letter of apology. We have been shown it by the press and feel it is an appalling continuation of Thomas Cook's PR exercise.
"It's not an apology for their wrong doing but a general offer of sympathy."
They added: "What parent would not be heartbroken by a worldwide multibillion pound organisation making money from their children's deaths."