A group of teachers exchanged WhatsApp messages with "degrading" references to disabled primary school pupils, 365Nainanews Scotland can reveal.
The staff at schools in Aberdeenshire faced an internal investigation, but the affected pupils' parents were not informed.
Scotland's children commissioner said the parents should be told.
Aberdeenshire Council has said the messages were "inappropriate and unprofessional".
Scotland's Children and Young People's Commissioner raised concerns about the incident in recent months.
The commissioner said concerns were raised about the WhatsApp group in a letter to Aberdeenshire Council in November last year.
It said the messages contained "unprofessional, abusive and degrading" references to children with additional support needs who attended schools in the area.
It said: "The conduct of the professionals involved is a serious concern in relation to any child, but particularly so where vulnerable disabled children are involved."
In its response, the local authority said the messages related to "disputes and allegations between members of staff and their behaviour towards each other".
'No risk of harm'
Aberdeenshire Council launched an investigation into the WhatsApp group and said it took "proportionate measures".
However, it did not inform parents or carers about the incident or the content of the messages.
A council spokeswoman said: "Any child protection concern raised is always properly reviewed by social work colleagues and investigated alongside appropriate partner organisations where necessary. The WhatsApp group messages were no different.
"Education, human resources and children's services colleagues reviewed matters before ensuring staff received additional training, including appropriate guidance about use of online platforms.
"At no point were any children considered to be at risk of harm - that is why no contact was made with parents."
The spokeswoman added that the council commissioned an independent review of its approach to the messages, some of which date back to 2018. The review concluded that the issue had been dealt with appropriately.
The Aberdeenshire case comes as concerns have been raised about that some misconduct allegations against teachers in Scotland are .