Education bosses have vowed to help turn around failing schools.
Ten Sussex schools were in special measures on April 8 Ofsted bosses announced yesterday.
In Brighton and Hove, Portslade Community College in Chalky Road, which is due to become an academy in September, is the only school in special measures.
Five East Sussex schools are in the same category, they include Pells Church of England Primary, in Lewes, Hurst Green Church of England, Chiddingly Primary, Southdown Junior School, in Newhaven and King Offa Primary, in Bexhill.
In West Sussex Heyworth Primary, in Haywards Heath, Por tfield Community Primary, in Chichester, Three Bridges Junior and Chesswood Middle School, in Worthing are all in special measures.
Three schools are also on notice to improve, which means they have the potential to improve under their current leadership and will be revisited within a year.
They include Whitehawk Primary School in Brighton and Sandown Primary, in Hatsings and The Lindfield School in Eastbourne.
Council bosses said staff at the schools are being offered additional support to help improve standards.
A Brighton and Hove City Council spokesman said: “The support we have given Whitehawk Primary was described as ‘well targeted’ by Ofsted when they visited the school recently to monitor its progress.
“Ofsted were very positive about Whitehawk and the work they are doing and we are confident that the school will come out of notice to improve at the next inspection.
“Ofsted monitoring visits have also praised the support we have given Portslade Community College in helping the school make satisfactory prog ress over this year, with teaching pupil prog ress seen as much improved.”
A spokesman for East Sussex County Council said: “It is always disappointing when a school is in this situation.
“In each case we are working with the headteacher, school governors and staff so that the schools can be taken out of special measures and improve as quickly as possible.”
A spokesman for West Sussex County Council said: “A great deal of work and support does go into schools to improve outcomes and all key local stakeholders, such as parents, are always kept fully informed.
“In all schools, leadership was strengthened either through the appointment of additional local authority governors or the establishment of an Interim Executive Board (IEB) at Heyworth and the allocation of an experienced local authority consultant head or lead adviser.