The health board said it is prioritising the children who are most sick, due to an unusually high number of referrals and pressure on beds and staffing.
Officials also warned that, heading into a local holiday weekend, services are expected to be busy and waits may be longer than usual.
But parents with concerns about their child’s health have still been urged to seek help.
It comes after NHS Lothian postponed non-urgent surgeries at the Royal Hospital for Children and Young People earlier this month, also under staffing pressure.
NHS Grampian said in a statement: “Please be aware that RACH is experiencing significant pressure on staffing and beds, due to an unusually high number of referrals for the time of year. This means we are prioritising those children who are most sick.
"We are asking all families to be patient, as their visit to the hospital may take longer than expected – this applies to both appointments and unscheduled attendances. This also means some procedures or operations, which are less urgent, have been, or could be, postponed.
This is always a last resort for us, and we are asking for your understanding at this time. Any cancellations will be rescheduled for the earliest possible date.
Scottish Conservative Shadow Cabinet Secretary for Health and Social Care, Dr Sandesh Gulhane, said in response to the move: “Health boards including NHS Grampian are at breaking point and this critical situation has been laid bare by the postponement of procedures at Royal Aberdeen Children's Hospital.”