| School | HMC Division | Membership | Location | Age Range |
| St Paul’s School, Brazil | International | International | São Paulo, Brazil | 3 - 18 |
| St Paul’s Girls’ School | London (UK) | British Isles | Hammersmith, London, United Kingdom | 11 - 18 |
| St Paul’s School | London (UK) | British Isles | Barnes, London, United Kingdom | 7 - 18 |
| St Peter’s School | North East (UK) | British Isles | York, United Kingdom | 2 - 18 |
| St Swithun’s School | South Central (UK) | British Isles | Winchester, United Kingdom | 11 - 18 |
| Stockport Grammar School | North West (UK) | British Isles | Stockport, United Kingdom | 3 - 18 |
| Stonyhurst College | North West (UK) | British Isles | Clitheroe, United Kingdom | 3 - 18 |
| Stowe School | East (UK) | British Isles | Stowe, United Kingdom | 13 - 18 |
| Strathallan School | Scottish (UK) | British Isles | Perth, United Kingdom | 9 - 18 |
| Streatham & Clapham High School | London (UK) | British Isles | Streatham, London, United Kingdom | 3 - 18 |
| Surbiton High School | London (UK) | British Isles | Kingston-upon-Thames, Surrey, United Kingdom | 4 - 18 |
| Sutton Valence School | South East (UK) | British Isles | Sutton Valence, United Kingdom | 2 - 18 |
| Sydney Grammar School | International | International | Darlinghurst, Australia | 4 - 18 |
| Tanglin Trust School | International | International | Queenstown, Singapore | 3 - 18 |
| Taunton School | South West (UK) | British Isles | Taunton, United Kingdom | 0 - 18 |
| The Abbey School, Reading | South Central (UK) | British Isles | Reading, United Kingdom | 3 - 18 |
| The British School in the Netherlands | International | International | Voorschoten, Netherlands | 3 - 18 |
| The British School of Amsterdam | International | International | Amsterdam, Netherlands | 3 - 18 |
| The British School of Barcelona | International | International | Barcelona, Spain | 2 - 18 |
| The British School of Brussels | International | International | Brussels, Belgium | 1 - 18 |
| The British School of Milan | International | International | Milan, Italy | 3 - 18 |
| The British School of Paris | International | International | Paris, France | 3 - 18 |
| The British School, New Delhi | International | International | New Delhi, India | 3 - 18 |
| The Bury Grammar Schools | North West (UK) | British Isles | Bury, United Kingdom | 3 - 18 |
| The Cathedral School, Llandaff | South West (UK) | British Isles | Cardiff, United Kingdom | 3 - 18 |
| The Dean Close Foundation | West (UK) | British Isles | Cheltenham, United Kingdom | 2 - 18 |
| The Doon School | International | International | Dehradun, India | 12 - 18 |
| The Edinburgh Academy | Scottish (UK) | British Isles | Edinburgh, United Kingdom | 2 - 18 |
| The English College in Prague | International | International | Prague, Czech Republic | 13 - 18 |
| The English School | International | International | Nicosia, Cyprus | 11 - 18 |
| The Glasgow Academy | Scottish (UK) | British Isles | Glasgow, United Kingdom | 3 - 18 |
| The Godolphin and Latymer School | London (UK) | British Isles | Hammersmith, London, United Kingdom | 11 - 18 |
| The Grammar School at Leeds | North East (UK) | British Isles | Leeds, United Kingdom | 3 - 18 |
| The Grange School | North West (UK) | British Isles | Northwich, United Kingdom | 4 - 18 |
| The Grange School, Santiago | International | International | La Reina, Chile | 3 - 18 |
| The Judd School | South East (UK) | Associate (UK) | Tonbridge, United Kingdom | 11 - 18 |
St Paul’s School, Brazil
Age range
3 - 18
Location
Rua Juquiá, 166 - Jardim Paulistano, São Paulo - SP, 01440-020, Brazil
Head’s name
Titus Edge
St Paul’s Girls’ School
Age range
11 - 18
Location
Brook Green, Hammersmith, London, W6 7BS, United Kingdom
Head’s name
Sarah Fletcher
St Paul’s School
Age range
7 - 18
Location
Lonsdale Road, Barnes, London, SW13 9JT, United Kingdom
Head’s name
Sally-Anne Huang
St Peter’s School
Age range
2 - 18
Location
St Peter's School, York, North Yorkshire, YO30 6AB, United Kingdom
Head’s name
Jeremy Walker
St Swithun’s School
Age range
11 - 18
Location
Alresford Road, Winchester, Hampshire, SO21 1HA, United Kingdom
Head’s name
Jane Gandee
Stockport Grammar School
Age range
3 - 18
Location
Buxton Road, Stockport, Cheshire, SK2 7AF, United Kingdom
Head’s name
Sarah Capewell
Stonyhurst College
Age range
3 - 18
Location
Stonyhurst, Clitheroe, Lancashire, BB7 9PZ, United Kingdom
Head’s name
John Browne
Stowe School
Age range
13 - 18
Location
Stowe, Buckingham, MK18 5EH, United Kingdom
Head’s name
Anthony Wallersteiner
Strathallan School
Age range
9 - 18
Location
Forgandenny, Perth, Scotland, PH2 9EG, United Kingdom
Head’s name
Mark Lauder
Streatham & Clapham High School
Age range
3 - 18
Location
42 Abbotswood Road, London, SW16 1AW, United Kingdom
Head’s name
Cathy Ellott
Surbiton High School
Age range
4 - 18
Location
13-15 Surbiton Crescent, Kingston-upon-Thames, Surrey, KT1 2JT, United Kingdom
Head’s name
Rebecca Glover
Sutton Valence School
Age range
2 - 18
Location
North Street, Sutton Valence, Kent, ME17 3HL, United Kingdom
Head’s name
James Thomas
Sydney Grammar School
Age range
4 - 18
Location
College Street, Darlinghurst NSW 2010, Australia
Head’s name
Richard Malpass
Tanglin Trust School
Age range
3 - 18
Location
95 Portsdown Road, Singapore, 139299
Head’s name
Craig Considine
Taunton School
Age range
0 - 18
Location
Staplegrove Road, Taunton, Somerset, TA2 6AD, United Kingdom
Head’s name
James Johnson
The Abbey School, Reading
Age range
3 - 18
Location
30 Christchurch Road, Reading, Berkshire, RG2 7AR, United Kingdom
Head’s name
William Le Fleming
The British School in the Netherlands
Age range
3 - 18
Location
Boerderij Rosenburgh, Voorschoten, 2252BA, The Netherlands
Head’s name
James Oxlade
The British School of Amsterdam
Age range
3 - 18
Location
Havenstraat 6, 1075PR, Amsterdam, The Netherlands
Head’s name
Ruth Sanderson
The British School of Barcelona
Age range
2 - 18
Location
Carrer Ginesta 26, 08860 Castelldefels, Barcelona, Spain
Head’s name
James Petrie
The British School of Brussels
Age range
1 - 18
Location
Pater Dupierreuxlaan 1, 3080 Tervuren, Belgium
Head’s name
Melanie Warnes
The British School of Milan
Age range
3 - 18
Location
Via Carlo Alberto Pisani Dossi, 16, 20134 Milano MI, Italy
Head’s name
Simon Lockyer
The British School of Paris
Age range
3 - 18
Location
38 Quai de l'Écluse, 78290 Croissy, Paris, France
Head’s name
Nicholas Hammond
The British School, New Delhi
Age range
3 - 18
Location
Doctor Jose P Rizal Marg, Chanakyapuri, New Delhi, Delhi, India
Head’s name
Vanita Uppal
The Bury Grammar Schools
Age range
3 - 18
Location
Bury Grammar School, Tenterden Street, Bury, Lancashire, BL9 0HN, United Kingdom
Head’s name
Jo Anderson
The Cathedral School, Llandaff
Age range
3 - 18
Location
Cardiff Road, Cardiff, Wales, CF5 2YH, United Kingdom
Head’s name
Clare Sherwood
The Dean Close Foundation
Age range
2 - 18
Location
Shelburne Road, Cheltenham, Gloucestershire, GL51 6HE, United Kingdom
Head’s name
Emma Taylor
The Doon School
Age range
12 - 18
Location
Mall Road, Krishna Nagar, Dehradun, Uttarakhand 248001, India
Head’s name
Jagpreet Singh
The Edinburgh Academy
Age range
2 - 18
Location
42 Henderson Row, Edinburgh, EH3 5BL, United Kingdom
Head’s name
Barry Welsh
The English College in Prague
Age range
13 - 18
Location
Sokolovska 320, Prague 9, 190 00, Czechia
Head’s name
Nigel Brown
The English School
Age range
11 - 18
Location
1 Presidential Palace Avenue, Nicosia, Strovolos, CY-1684, Cyprus
Head’s name
Stuart Walker
The Glasgow Academy
Age range
3 - 18
Location
Colebrooke Street, Glasgow, Scotland, G12 8HE, United Kingdom
Head’s name
Matthew Pearce
The Godolphin and Latymer School
Age range
11 - 18
Location
Iffley Road, Hammersmith, London, W6 0PG, United Kingdom
Head’s name
Frances Ramsey
The Grammar School at Leeds
Age range
3 - 18
Location
Alwoodley Gates, Harrogate Road, Leeds, LS17 8GS, United Kingdom
Head’s name
Sue Woodroofe
The Grange School
Age range
4 - 18
Location
Bradburns Lane, Hartford, Northwich, Cheshire, CW8 1LU, United Kingdom
Head’s name
Lorraine Earps
The Grange School, Santiago
Age range
3 - 18
Location
Príncipe de Gales 6154, La Reina, Región Metropolitana, Chile
Head’s name
Nicholas Eatough
The Judd School
Age range
11 - 18
Location
Brook Street, Tonbridge, TN9 2PN, United Kingdom
Head’s name
Jon Woods