Sir John Nelthorpe School
|Type||Voluntary controlled comprehensive|
|Headteacher||Mr Robert Biglands|
|Founder||Sir John Nelthorpe|
|Location||Grammar School Road
|Local authority||North Lincolnshire|
|DfE URN||118112 Tables|
|Chair of Governors||Mrs E Wells|
The school, also referred to as SJN, was formed as a grammar school in 1669 by Sir John Nelthorpe, who was born in Brigg in 1614. He was unmarried and wanted his wealth from his estate across Lincolnshire to create a school in his name. The buildings were opened around 1680, and the Upper School Library dates from this time. New buildings were added in 1879, and the Nelthorpe family have retained strong links with the school.
The grammar school in the 1970s had around 350 boys. Brigg Girls' High School, on Wrawby Road, had around 250 girls, and became the lower school. These schools were administered until 1974 by the Lindsey Education Committee, based in Lincoln.
It became a co-educational comprehensive in 1976.
Recent improvements have included a new canteen, full refurbishment of the drama hall and science labs, redecoration of English classrooms and improved security. The school was one of two in Humberside LEA that had a boarding house; Bridlington School (a former grammar school) was the other. Since 1996 it has been administered by North Lincolnshire; the LEA's offices are in Brigg.
The school offers a variety of subjects, with a wider range of options being introduced for year ten to take into account different learning pathways. It shares the sixth form, known as the Brigg Sixth Form College, with the town's other comprehensive school, The Vale Academy. Brigg Sixth Form has a partnership with Baysgarth School sixth form, allowing students to opt for a wider range of subjects. 'A' level results have traditionally been high, with many subjects placed in the national top 25%. There is a strong emphasis on the wider curriculum, with successful expeditions to Malawi (2012) and India (2014)  and major Great War research project supported by the Heritage Lottery Fund. Its students are currently district netball and cricket champions and winners of the Magistrates Mock Trial competition.
Students are well-behaved, welcome responsibilities, socialise sensibly and are tolerant of and show respect for each other and adults.
- In many lessons students are provided with imaginative, stimulating and challenging activities that meet their needs appropriately.
- Students in Key Stage 4 achieve well and attain standards higher than that seen nationally. The performance of students supported by pupil premium funding is improving.
- The progress made by lower-ability students is tracked carefully and effective additional support is given to help them improve their progress.
Sir John Nelthorpe was labelled good in 2014.
Current academic performance
In recent years GCSE results have been consistent at over 70% A*-C. In 2015, 74% of students achieved 5 grades A* to C including English and maths, and 46% achieved the Ebacc, both figures the highest in North Lincolnshire 
Notable former pupils
Brigg Grammar School
- William Eric Grasar (1924–31), Roman Catholic Bishop of Shrewsbury 1962-80
- Robert Hudson (1934–41), Professor of Organic Chemistry from 1967-85 at the University of Kent
- Eric Waldram Kemp (1926–33), Bishop of Chichester 1974-2001
- Kenneth Jones (1932-9), High Court Judge (died 2004), who prosecuted the Kray Twins
- John Pimlott (1959–66), military historian
- Alexander Trees, Baron Trees, Professor of veterinary parasitology and Crossbench member of the House of Lords
Sir John Nelthorpe School
- Rob Waltham, (Conservative) Leader since 2017 of North Lincolnshire Council
- David Yelland, former editor of The Sun from 1998–2003, from 1976 to1981.
Brigg Girls' High School
- School website
- Making multimedia in ICT
- Old Briggensians
- 2007 School Prom photo gallery taken at Elsham Hall