Over the last two weeks seven schools have been broken into in the south east of the city, with burglaries reported in Birley, Hackenthorpe, Handsworth and Westfield.
The latest was at Mosborough Primary overnight after a window was smashed to gain entry.
It is not yet known what was stolen.
Detectives investigating the incidents said there have also been school raids reported in Wales, Aston, Heeley and Eckington.
Inspector Jason Booth said: "Over the last two weeks we have seen an unusual increase in schools being broken into overnight.
"Doors have been kicked in and windows smashed to gain entry, with items such as electrical and small amounts of cash taken.
"So far we have had seven schools attacked in Birley, Hackenthorpe, Handsworth and Westfield. We are also aware of burglaries just outside our area in Wales, Aston, Heeley and Eckington.
Clearly these crimes impact on what is a valuable community resource and causes a significant impact on children's education as well as the financial loss to the schools of valuable equipment.
"We are exploring any lines of enquiry with the investigations but we need community support.
If you have any information about who may be involved in these crimes please call us."
St John Fisher Catholic Primary School, Springwater Avenue, Hackenthorpe, was broken into earlier this week.
A touch screen monitor was stolen during the raid.
Cash and collection boxes were taken during a break-in at Westfield School, Westfield, in the early hours of Thursday, September 28.
On Sunday, September 17, a petrol strimmer was stolen from a plant room at Outwood Academy, Stradbroke Road, Stradbroke.
Anyone with information should call South Yorkshire Police on 101 or Crimestoppers on 0800 555111.