A window was smashed to gain entry but it is not yet known what was stolen.
The six other break-ins under investigation by the Sheffield South East neighbourhood policing team occurred at Birley Spa Community Primary School, Birley College and Birley Primary Academy School, Birley; Westfield School, Westfield; Handsworth Grange Community Sports College School, Handsworth and St John Fisher Catholic Primary School, Hackenthorpe.
Officers are looking for possible links between the burglaries and a number of other break-ins reported in nearby Wales, Aston, Heeley, Stradbroke and Eckington.
A touch screen monitor was stolen from St John Fisher Catholic Primary School earlier this week and Carrfield Schoool in Heeley was broken into over the weekend after a glass door was smashed.
Cash and collection boxes were taken during a break-in at Westfield School in the early hours of Thursday, September 28 and on Sunday, September 17, a petrol strimmer was stolen from a plant room at Outwood Academy, Stradbroke Road, Stradbroke.
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.
"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."
He said the offences may be linked.
"We are keeping an open mind as to whether the offences are linked. Someone knows who is involved and we need them to come forward," he added.
"Schools are a community resource and those breaking in need to understand the impact they are having on children and their education.
"Nothing of great value is being stolen, it's odd bits of cash in school offices for example, but it is the damage that is caused and the disruption that impacts on staff and children."
Insp Booth urged local residents to report suspicious behaviour around schools.
"We are carrying out visible patrols around schools and we are visiting them to discuss their security and to offer help with mark up valuable items," he added.
"It is also important that local residents remain vigilant and report any suspicious behaviour around schools because the more information we have the better chance we have of detecting these offences."
Anyone with information should call South Yorkshire Police on 101 or Crimestoppers on 0800 555111.