| School | HMC Division | Membership | Location | Age Range |
| Magdalen College School | South Central (UK) | British Isles | Oxford, United Kingdom | 7 - 18 |
| Malvern College | West (UK) | British Isles | Malvern, United Kingdom | 13 - 18 |
| Manchester High School for Girls | North West (UK) | British Isles | Manchester, United Kingdom | 4 - 18 |
| Markham College | International | International | Lima, Peru | 3 - 18 |
| Marlborough College | South Central (UK) | British Isles | Marlborough, United Kingdom | 13 - 18 |
| Marlborough College, Malaysia | International | International | Iskandar Puteri, Malaysia | 3 - 18 |
| Merchant Taylors’ Boys’ School, Crosby | North West (UK) | British Isles | Liverpool, United Kingdom | 4 - 18 |
| Merchant Taylors’ School, Northwood | London (UK) | British Isles | Hillingdon, London, United Kingdom | 11 - 18 |
| Merchiston Castle School | Scottish (UK) | British Isles | Edinburgh, United Kingdom | 7 - 18 |
| Methodist College (Belfast) | Irish | British Isles | Belfast, United Kingdom | 11 - 18 |
| Michaelhouse | International | International | Balgowan, South Africa | 13 - 18 |
| Millfield School | South West (UK) | British Isles | Street, United Kingdom | 13 - 18 |
| Monkton Combe School | South West (UK) | British Isles | Bath, United Kingdom | 13 - 18 |
| Morrison’s Academy | Scottish (UK) | British Isles | Crieff, United Kingdom | 2 - 18 |
| Mount Kelly | South West (UK) | British Isles | Tavistock, United Kingdom | 3 - 18 |
| Mount St Mary’s College | North East (UK) | British Isles | Sheffield, United Kingdom | 3 - 18 |
| New Hall School | London (UK) | British Isles | Chelmsford, United Kingdom | 1 - 18 |
| Newcastle High School for Girls | North East (UK) | British Isles | Newcastle upon Tyne, United Kingdom | 3 - 18 |
| Newcastle upon Tyne Royal Grammar School | North East (UK) | British Isles | Newcastle upon Tyne, United Kingdom | 8 - 18 |
| Newcastle-under-Lyme School | North West (UK) | British Isles | Newcastle-Under-Lyme, United Kingdom | 2 - 18 |
| North London Collegiate School | London (UK) | British Isles | Edgware, United Kingdom | 4 - 18 |
| Norwich High School for Girls | East (UK) | British Isles | Norwich, United Kingdom | 3 - 18 |
| Norwich School | East (UK) | British Isles | Norwich, United Kingdom | 4 - 18 |
| Notting Hill and Ealing High School | London (UK) | British Isles | Ealing, London, United Kingdom | 4 - 18 |
| Nottingham High School | East (UK) | British Isles | Nottingham, United Kingdom | 4 - 18 |
| Oakham School | East (UK) | British Isles | Oakham, United Kingdom | 10 - 18 |
| Oswestry School | West (UK) | British Isles | Oswestry, United Kingdom | 4 - 18 |
| Oundle School | East (UK) | British Isles | Oundle, United Kingdom | 11 - 18 |
| Pangbourne College | South Central (UK) | British Isles | Reading, United Kingdom | 11 - 18 |
| Peponi School | International | International | Ruiru, Kenya | 13 - 18 |
| Peterhouse | International | International | Marondera, Zimbabwe | 4 - 18 |
| Pipers Corner School | London (UK) | British Isles | High Wycombe, United Kingdom | 4 - 18 |
| Plymouth College | South West (UK) | British Isles | Plymouth, United Kingdom | 3 - 18 |
| Pocklington School | North East (UK) | British Isles | Pocklington, United Kingdom | 2 - 18 |
| Princethorpe College | West (UK) | British Isles | Rugby, United Kingdom | 11 - 18 |
| Prior Park College | South West (UK) | British Isles | Bath, United Kingdom | 11 - 18 |
Magdalen College School
Age range
7 - 18
Location
Magdalen College, Oxford, OX4 1DZ, United Kingdom
Head’s name
Helen Pike
Malvern College
Age range
13 - 18
Location
College Road, Malvern, Worcestershire, WR14 3DF, United Kingdom
Head’s name
Keith Metcalfe
Manchester High School for Girls
Age range
4 - 18
Location
Grangethorpe Road, Manchester, England, M14 6HS, United Kingdom
Head’s name
Helen Jeys
Markham College
Age range
3 - 18
Location
Calle Augusto Angulo 291, Miraflores, Lima, Peru
Head’s name
Judy Cooper
Marlborough College
Age range
13 - 18
Location
Bath Road, Marlborough, Wiltshire, SN8 1PA, United Kingdom
Head’s name
Louise Moelwyn Hughes
Marlborough College, Malaysia
Age range
3 - 18
Location
Jalan Marlborough, Puteri Harbour, 79200 Iskandar Puteri, Johor, Malaysia
Head’s name
Alan Stevens
Merchant Taylors’ Boys’ School, Crosby
Age range
4 - 18
Location
186 Liverpool Rd, Crosby, Liverpool L23 0QW, United Kingdom
Head’s name
Michael Alderson
Merchant Taylors’ School, Northwood
Age range
11 - 18
Location
Sandy Lodge, Northwood, Middlesex, HA6 2HT, United Kingdom
Head’s name
Simon Everson
Merchiston Castle School
Age range
7 - 18
Location
294 Colinton Road, Edinburgh, Scotland, EH13 0PU, United Kingdom
Head’s name
Jonathan Anderson
Methodist College (Belfast)
Age range
11 - 18
Location
1 Malone Road, Belfast, BT9 6BY, United Kingdom
Head’s name
Jenny Lendrum
Michaelhouse
Age range
13 - 18
Location
R103, Balgowan, Kwazulu-Natal, South Africa
Head’s name
Antony Clark
Millfield School
Age range
13 - 18
Location
Millfield School, Street, Somerset, BA16 OYD, United Kingdom
Head’s name
Gavin Horgan
Monkton Combe School
Age range
13 - 18
Location
Monkton Combe School, Combe Down, Bath, BA2 7ET, United Kingdom
Head’s name
Chris Wheeler
Morrison’s Academy
Age range
2 - 18
Location
Ferntower Road, Crieff, Perthshire, Scotland, PH7 3AN, United Kingdom
Head’s name
Andrew McGarva
Mount Kelly
Age range
3 - 18
Location
Parkwood Road, Tavistock, Devon, PL19 OHZ, United Kingdom
Head’s name
Guy Ayling
Mount St Mary’s College
Age range
3 - 18
Location
College Road, Spinkhill, Near Sheffield, Derbyshire, S21 3YL, United Kingdom
Head’s name
Daniel Wright
New Hall School
Age range
1 - 18
Location
The Avenue, Chelmsford, Essex, CM3 3HS, United Kingdom
Head’s name
Katherine Jeffrey
Newcastle High School for Girls
Age range
3 - 18
Location
Tankerville Terrace, Newcastle upon Tyne, Tyne & Wear, NE2 3BA, United Kingdom
Head’s name
Amanda Hardie
Newcastle upon Tyne Royal Grammar School
Age range
8 - 18
Location
Eskdale Terrace, Jesmond, Newcastle Upon Tyne, NE2 4DX, United Kingdom
Head’s name
Geoffrey Stanford
Newcastle-under-Lyme School
Age range
2 - 18
Location
Mount Pleasant, Newcastle-Under-Lyme, Staffordshire, ST5 1DB, United Kingdom
Head’s name
Michael Getty
North London Collegiate School
Age range
4 - 18
Location
Canons, Canons Drive, Edgware, Middlesex, HA8 7RJ
Head’s name
Vicky Bingham
Norwich High School for Girls
Age range
3 - 18
Location
95 Newmarket Rd, Norwich, NR2 2HU, United Kingdom
Head’s name
Alison Sefton
Norwich School
Age range
4 - 18
Location
71a The Close, Norwich, NR1 4DD, United Kingdom
Head’s name
Steffan Griffiths
Notting Hill and Ealing High School
Age range
4 - 18
Location
2 Cleveland Road, Ealing, London, W13 9TZ, United Kingdom
Head’s name
Matthew Shoults
Nottingham High School
Age range
4 - 18
Location
Waverley Mount, Nottingham, NG7 4ED, United Kingdom
Head’s name
Kevin Fear
Oakham School
Age range
10 - 18
Location
Chapel Close, Oakham, Rutland, LE15 6QT, United Kingdom
Head’s name
Henry Price
Oswestry School
Age range
4 - 18
Location
Upper Brook Street, Oswestry, Shropshire, SY11 2TL, United Kingdom
Head’s name
Peter Middleton
Oundle School
Age range
11 - 18
Location
Great Hall, Oundle, Peterborough, PE8 4GH, United Kingdom
Head’s name
Sarah Kerr-Dineen
Pangbourne College
Age range
11 - 18
Location
Pangbourne, Reading, Berkshire, RG8 8LA, United Kingdom
Head’s name
Oliver Knight
Peponi School
Age range
13 - 18
Location
Off Thika Rd, Ruiru, Kenya
Head’s name
Mark Durston
Peterhouse
Age range
4 - 18
Location
P. Bag 3741, Marondera --263, Zimbabwe
Head’s name
Jonathan Trafford
Pipers Corner School
Age range
4 - 18
Location
Pipers Lane, Great Kingshill, High Wycombe, HP15 6LP
Head’s name
Helen Ness-Gifford
Plymouth College
Age range
3 - 18
Location
Ford Park, Plymouth, Devon, PL4 6RN, United Kingdom
Head’s name
Peter Watts
Pocklington School
Age range
2 - 18
Location
West Green, Pocklington, East Yorkshire, YO42 2NJ, United Kingdom
Head’s name
Toby Seth
Princethorpe College
Age range
11 - 18
Location
Princethorpe, Rugby, Warwickshire, CV23 9PX, United Kingdom
Head’s name
Ed Hester
Prior Park College
Age range
11 - 18
Location
Ralph Allen Drive, Bath, Banes, BA2 5AH, United Kingdom
Head’s name
Ben Horan