Mourne Mountain Rescue Team said one of the pupils was suffering from severe hypothermia and was lapsing in and out of consciousness while a number of others had mild symptoms. All have now recovered.
A total of 23 rescuers were involved in the operation on Monday night to bring the 11 members of the expedition group to safety, with additional support from paramedics.
The pupils, who are aged between 16 and 17, were in an isolated area of the mountains on the western flank of the Slieve Beg/Commedagh Col.
Linfield v Portadown Sunday clash: Breakers of the Sabbath will answer to God
NI Weather: 45 pictures of how we enjoyed wall-to-wall sunshine
Thousands expected to take part in 'Derry Day' this weekend
Esmond Birnie: The protocol is not as claimed boosting growth in Northern Ireland
Tom Topping: Heartbroken daughter says ‘world is totally shattered’ after father’s shock death - funeral details released
The rescue team praised the actions of the teenagers to seek shelter and help each other out when they got into trouble.
“Clearly, had it not been for the outstanding efforts of the young people in this group, this situation would have been much, much more serious,” said a Mourne Mountain Rescue Team statement.
The team received the distress call at around 7.15pm on Monday and the rescue operation concluded at 1.10am.
Martin McMullan who took part in the rescue operation told the News Letter they were thanked by those they had helped down from the mountain.
“The children involved thanked us last night,” he said.
Meanwhile countless messages of support and thanks flooded the Mourne Mountain Rescue Team Facebook page.
Messages included: “Fantastic work! Well done, and well done to the kids coping so well too. Big hugs to all the frantic parents too, can’t imagine what a worry that was!” and “Amazing job by all the rescue team!”.