More than 1,000 children contacted Childline on Christmas Day.
The ISPCC say some kids contacted them as they were finding Christmas tough following the loss of a loved one, or that they were feeling sad or lonely.
They say the impact of alcohol abuse in the home was also apparent from some of the calls they received.
A team of 61 volunteers staffed the Childline helpline on Christmas Day, taking 1,049 messages from children via phone, webchat and text.
ISPCC Chief Executive Grainia Long said: "Christmas should mean safety, warmth and happiness, but for many children that call our Childline service, this isn’t the reality.
"Some children who contacted Childline on Christmas day are experiencing loneliness, loss and domestic violence over this festive period which makes what should be a happy time very difficult for them but thanks to our dedicated volunteers, Childline is here to listen and support them.
"We would like to thank sincerely our volunteers for giving up their Christmas day in order to listen to these children. Childline is here for children every day of the year and we couldn’t provide this essential service without the support of our dedicated, committed and highly-trained volunteers."
By phone: Children and young people can contact Childline’s 24 hour phone service by phoning 1800 666666.
By text: Text the word: ‘talk’ to 50101 (service available from 10am to 4am)
Live online chat: Available from 10am to 4am, live chat on Childline.ie
Via the web: You will find various items of support and advice for children and parents on ispcc.ie and childline.ie