| School | HMC Division | Membership | Location | Age Range |
| The Manchester Grammar School | North West (UK) | British Isles | Manchester, United Kingdom | 7 - 18 |
| The Maynard School | South West and Wales (UK) | British Isles | Exeter, Devon | 4 - 18 |
| The Mill Hill School Foundation | London (UK) | British Isles | Barnet, London, United Kingdom | 3 - 18 |
| The Oratory School | South Central (UK) | British Isles | Woodcote, Near Reading, United Kingdom | 11 - 18 |
| The Perse School | East (UK) | British Isles | Cambridge, United Kingdom | 3 - 18 |
| The Portsmouth Grammar School | South Central (UK) | British Isles | Portsmouth, United Kingdom | 2 - 18 |
| The Radley Schools Group | South Central (UK) | British Isles | Oxon, United Kingdom | 13 - 18 |
| The Royal Belfast Academical Institution | Irish | British Isles | Belfast, United Kingdom | 11 - 18 |
| The Royal School Armagh | Irish | British Isles | Armagh, United Kingdom | 4 - 18 |
| The Royal School, Dungannon | Irish | British Isles | Dungannon, United Kingdom | 11 - 18 |
| The Scots College | International | International | Sydney, Australia | 3 - 18 |
| The Stamford Endowed Schools | East (UK) | British Isles | Stamford, United Kingdom | 2 - 18 |
| The Stephen Perse Foundation | East (UK) | British Isles | Cambridge, United Kingdom | 1 - 18 |
| Tonbridge School | South East (UK) | British Isles | Tonbridge, United Kingdom | 13 - 18 |
| Tormead School | South Central (UK) | British Isles | Guildford, United Kingdom | 4 - 18 |
| Tranby | North East (UK) | British Isles | Anlaby, United Kingdom | 3 - 18 |
| Trent College | East (UK) | British Isles | Nottingham, United Kingdom | 0 - 18 |
| Trinity School | London (UK) | British Isles | Croydon, London, United Kingdom | 10 - 18 |
| Truro School | South West and Wales (UK) | British Isles | Truro, United Kingdom | 3 - 18 |
| United Lisbon International School | International | Associate (International) | Lisboa, Portugal | 3 - 18 |
| University College School | London (UK) | British Isles | Hampstead, London, United Kingdom | 11 - 18 |
| Uppingham Cairo | International | Associate (International) | , Egypt | 11 - 18 |
| Uppingham School | East (UK) | British Isles | Uppingham, United Kingdom | 13 - 18 |
| Victoria College | South West and Wales (UK) | British Isles | St Helier, United Kingdom | 11 - 18 |
| Warminster School | South West and Wales (UK) | British Isles | Warminster, United Kingdom | 2 - 18 |
| Warwick Independent Schools Foundation | West (UK) | British Isles | Warwick, United Kingdom | 11 - 18 |
| Wellingborough School | East (UK) | British Isles | Wellingborough, United Kingdom | 3 - 18 |
| Wellington College | South Central (UK) | British Isles | Crowthorne, United Kingdom | 13 - 18 |
| Wellington College International Shanghai | International | International | , China | 2 - 18 |
| Wellington School | South West and Wales (UK) | British Isles | Wellington, United Kingdom | 3 - 18 |
| Wells Cathedral School | South West and Wales (UK) | British Isles | Wells, United KIngdom | 2 - 18 |
| Wesgreen International School | International | International | Sharjah, United Arab Emirates | 4 - 18 |
| West Buckland School | South West and Wales (UK) | British Isles | Barnstaple, United Kingdom | 3 - 18 |
| Westminster School | London (UK) | British Isles | Westminster, London, United Kingdom | 13 - 18 |
| Whitgift School | London (UK) | British Isles | South Croydon, Surrey, United Kingdom | 10 - 18 |
| Wimbledon High School | London (UK) | British Isles | Wimbledon, London, United Kingdom | 4 - 18 |
The Manchester Grammar School
Age range
7 - 18
Location
Old Hall Lane, Manchester M13 0XT, United Kingdom
Head’s name
Martin Boulton
The Maynard School
Age range
4 - 18
Location
Denmark Road Exeter Devon EX1 1SJ
Head’s name
Liz Gregory
The Mill Hill School Foundation
Age range
3 - 18
Location
The Ridgeway, London, NW7 1QS, United Kingdom
Head’s name
Antony Spencer
The Oratory School
Age range
11 - 18
Location
Woodcote, Near Reading, South Oxfordshire, RG8 0PJ, United Kingdom
Head’s name
Matthew Fogg
The Perse School
Age range
3 - 18
Location
80 Glebe Rd, Cambridge, Cambridgeshire, CB17SZ, United Kingdom
Head’s name
Ed Elliott
The Portsmouth Grammar School
Age range
2 - 18
Location
High Streett, Portsmouth, Hampshire, PO1 2LN, United Kingdom
Head’s name
David Wickes
The Radley Schools Group
Age range
13 - 18
Location
Abingdon, Oxon, Oxfordshire, OX14 2HR, United Kingdom
Head’s name
John Moule
The Royal Belfast Academical Institution
Age range
11 - 18
Location
College Square East, Belfast, Co. Antrim, Northern Ireland, BT1 6DL, United Kingdom
Head’s name
Janet Williamson
The Royal School Armagh
Age range
4 - 18
Location
College Hill, Armagh, Northern Ireland, BT61 9DH, United Kingdom
Head’s name
Graham Montgomery
The Royal School, Dungannon
Age range
11 - 18
Location
2 Ranfurly Road, Dungannon, Northern Ireland, BT71 6EG, United Kingdom
Head’s name
David Burnett
The Scots College
Age range
3 - 18
Location
53 Victoria Rd, Bellevue Hill, Sydney, NSW 2023, Australia
Head’s name
Ian Lambert
The Stamford Endowed Schools
Age range
2 - 18
Location
Brazenose House, St. Paul’s Street, Stamford, Lincolnshire, PE9 2BE, United Kingdom
Head’s name
Chris Seal
The Stephen Perse Foundation
Age range
1 - 18
Location
Union Road, Cambridge, CB2 1HF, United Kingdom
Head’s name
Richard Girvan
Tonbridge School
Age range
13 - 18
Location
High Street, Tonbridge, Kent, TN9 1JP, United Kingdom
Head’s name
James Priory
Tormead School
Age range
4 - 18
Location
Cranley Road, Guildford, Surrey, GU1 2JD, United Kingdom
Head’s name
David Boyd
Tranby
Age range
3 - 18
Location
Tranby Croft, Anlaby, East Yorkshire, HU10 7EH, United Kingdom
Head’s name
Chris Wainman
Trent College
Age range
0 - 18
Location
Derby Road, Nottingham, Derbyshire, NG10 4AD, United Kingdom
Head’s name
Bill Penty
Trinity School
Age range
10 - 18
Location
Shirley Park, Croydon, London, CR9 7AT, United Kingdom
Head’s name
Alasdair Kennedy
Truro School
Age range
3 - 18
Location
Trennick Lane, Truro, Cornwall, TR1 1TH, United Kingdom
Head’s name
Andrew Johnson
United Lisbon International School
Age range
3 - 18
Location
Avenida Marechal Gomes da Costa, Lisbon, Portugal
Head’s name
Martin Harris
University College School
Age range
11 - 18
Location
Frognal, Hampstead, London, NW3 6XH, United Kingdom
Head’s name
Mark Beard
Uppingham Cairo
Age range
11 - 18
Location
New Giza, KM 22 Cairo - Alex Road, First 6th of October, Giza Governorate
Head’s name
Emma Webb
Uppingham School
Age range
13 - 18
Location
Uppingham School, Uppingham, Rutland, LE15 9QE, United Kingdom
Head’s name
Richard Maloney
Victoria College
Age range
11 - 18
Location
Mont Millais, St Helier, Jersey, JE1 4HT, United Kingdom
Head’s name
Gareth Hughes
Warminster School
Age range
2 - 18
Location
Church Street, Warminster, Wiltshire, BA12 8PJ, United Kingdom
Head’s name
Matt Williams
Warwick Independent Schools Foundation
Age range
11 - 18
Location
Myton Road, Warwick, CV34 6PP, United Kingdom
Head’s name
Richard Nicholson
Wellingborough School
Age range
3 - 18
Location
London Road, Wellingborough, Northants, NN8 2BX, United Kingdom
Head’s name
Simon Hawkes
Wellington College
Age range
13 - 18
Location
Dukes Ride, Crowthorne, Berkshire, RG45 7PU, United Kingdom
Head’s name
James Dahl
Wellington College International Shanghai
Age range
2 - 18
Location
No. 1500 Yao Long Road, Pudong New District, Shanghai 200124 China
Head’s name
Julian Jeffrey
Wellington School
Age range
3 - 18
Location
South Street, Wellington, Somerset, TA21 8NT, United Kingdom
Head’s name
Alex Battison
Wells Cathedral School
Age range
2 - 18
Location
15, The Liberty, Wells, Somerset, BA5 2ST, United KIngdom
Head’s name
Alastair Tighe
Wesgreen International School
Age range
4 - 18
Location
Al Muweilah Commercial Sharjah, United Arab Emirates
Head’s name
James McDonald
West Buckland School
Age range
3 - 18
Location
Barnstaple, North Devon, EX32 0SX, United Kingdom
Head’s name
Helen Lowe
Westminster School
Age range
13 - 18
Location
17 Dean's Yard, Westminster, London, SW1P 3PB, United Kingdom
Head’s name
Gary Savage
Whitgift School
Age range
10 - 18
Location
Haling Park, Croydon, Surrey, CR2 6YT, United Kingdom
Head’s name
To be confirmed
Wimbledon High School
Age range
4 - 18
Location
Mansel Road, Wimbledon, Greater London, SW19 4AB, United Kingdom
Head’s name
Fionnuala Kennedy