| School | HMC Division | Membership | Location | Age Range |
| King’s Ely | East (UK) | British Isles | Ely, United Kingdom | 2 - 18 |
| King’s School Rochester | South East (UK) | British Isles | Rochester, United Kingdom | 3 - 18 |
| Kingston Grammar School | London (UK) | British Isles | Kingston upon Thames, Surrey, United Kingdom | 11 - 18 |
| Kingswood School, Bath | South West and Wales (UK) | British Isles | Bath, United Kingdom | 11 - 18 |
| Kirkham Grammar School | North West (UK) | British Isles | Preston, United Kingdom | 3 - 18 |
| Kolej Tuanku Ja’afar | International | International | Mantin, Malaysia | 4 - 18 |
| Lady Eleanor Holles School | London (UK) | British Isles | Hampton, Richmond upon Thames, United Kingdom | 7 - 18 |
| Lancing College | South East (UK) | British Isles | Lancing, United Kingdom | 13 - 18 |
| Langley School | East (UK) | British Isles | Norwich, United Kingdom | 2 - 18 |
| Latymer Upper School | London (UK) | British Isles | Hammersmith, London, United Kingdom | 11 - 18 |
| Leicester Grammar School | East (UK) | British Isles | Leicester, United Kingdom | 3 - 18 |
| Leighton Park School | South Central (UK) | British Isles | Reading, United Kingdom | 11 - 18 |
| Lincoln Minster School | East (UK) | British Isles | Lincoln, United Kingdom | 4 - 18 |
| Lingfield College | South East (UK) | British Isles | Lingfield, United Kingdom | 2 - 18 |
| Lomond School | Scottish (UK) | British Isles | Helensburgh, United Kingdom | 3 - 18 |
| Lord Wandsworth College | South Central (UK) | British Isles | Long Sutton, United Kingdom | 11 - 18 |
| Loretto School | Scottish (UK) | British Isles | East Lothian, United Kingdom | 3 - 18 |
| Loughborough Grammar School | East (UK) | British Isles | Loughborough, United Kingdom | 10 - 18 |
| Loughborough Schools Foundation | East (UK) | British Isles | , | 0 - 18 |
| 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 |
| Mayfield School | South East (UK) | British Isles | Mayfield, United Kingdom | 11 - 18 |
| Merchant Taylors’ 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 and Wales (UK) | British Isles | Street, United Kingdom | 13 - 18 |
| Minerva Virtual Academy | International | Associate (International) | London, United Kingdom | 11 - 18 |
| Monkton Combe School | South West and Wales (UK) | British Isles | Bath, United Kingdom | 13 - 18 |
| Morrison’s Academy | Scottish (UK) | British Isles | Crieff, United Kingdom | 2 - 18 |
| Mount Kelly | South West and Wales (UK) | British Isles | Tavistock, United Kingdom | 3 - 18 |
King’s Ely
Age range
2 - 18
Location
The Old Palace, Ely, Cambridgeshire, CB7 4EW, United Kingdom
Head’s name
John Attwater
King’s School Rochester
Age range
3 - 18
Location
Satis House, Rochester, Kent, ME1 1TE, United Kingdom
Head’s name
Simon Fisher
Kingston Grammar School
Age range
11 - 18
Location
70 London Road, Kingston upon Thames, Surrey, KT2 6PY, United Kingdom
Head’s name
Stephen Lehec
Kingswood School, Bath
Age range
11 - 18
Location
Lansdown Road, Bath, BA1 5RG, United Kingdom
Head’s name
Andrew Gordon-Brown
Kirkham Grammar School
Age range
3 - 18
Location
Ribby Road, Preston, Lancashire, PR4 2BH, United Kingdom
Head’s name
To be confirmed
Kolej Tuanku Ja’afar
Age range
4 - 18
Location
Kolej Tuanku Ja'afar, Mantin, Negeri Sembilan, 71700, Malaysia
Head’s name
Glenn Moodie
Lady Eleanor Holles School
Age range
7 - 18
Location
102 Hanworth Road, Hampton, Middlesex, TW12 3HF, UK
Head’s name
Rowena Cole
Lancing College
Age range
13 - 18
Location
Lancing, West Sussex, BN15 0RW, United Kingdom
Head’s name
Scott Crawford
Langley School
Age range
2 - 18
Location
Langley Park, Loddon, Norwich, NR14 6BJ, United Kingdom
Head’s name
Simon Cooke
Latymer Upper School
Age range
11 - 18
Location
237 King Street, Hammersmith, London, W6 9LR, United Kingdom
Head’s name
Su Wijeratna
Leicester Grammar School
Age range
3 - 18
Location
London Road, Leicester, Leicestershire, LE8 9FL, United Kingdom
Head’s name
Graham Purves
Leighton Park School
Age range
11 - 18
Location
Shinfield Road, Reading, Berkshire, RG2 7ED, United Kingdom
Head’s name
Luke Walters
Lincoln Minster School
Age range
4 - 18
Location
Upper Lindrum Street, Lincoln, LN2 5RW, United Kingdom
Head’s name
Jon Tyler
Lingfield College
Age range
2 - 18
Location
St Piers Lane, Lingfield, Surrey, RH7 6PH, United Kingdom
Head’s name
Richard Bool
Lomond School
Age range
3 - 18
Location
10 Stafford Street, Helensburgh, Argyll & Bute, Scotland, G84 9JX, United Kingdom
Head’s name
Claire Chisholm
Lord Wandsworth College
Age range
11 - 18
Location
Long Sutton, Hampshire, RG29 1TB, United Kingdom
Head’s name
Adam Williams
Loretto School
Age range
3 - 18
Location
1-7 Linkfield Road, East Lothian, Scotland, EH21 7RE, United Kingdom
Head’s name
Pete Richardson
Loughborough Grammar School
Age range
10 - 18
Location
Burton Walks, Loughborough, Leicestershire, LE11 2DU, United Kingdom
Head’s name
James Neville
Loughborough Schools Foundation
Age range
0 - 18
Location
3 Burton Walks, Loughborough, LE11 2DU
Head’s name
Chris Staley
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
Simon Burbury
Mayfield School
Age range
11 - 18
Location
The Old Palace, Mayfield, East Sussex, TN20 6PH
Head’s name
Deborah Bligh
Merchant Taylors’ School, Crosby
Age range
4 - 18
Location
186 Liverpool Rd, Crosby, Liverpool L23 0QW, United Kingdom
Head’s name
Philip Dearden
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
Huw Jones
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
Win de Wet
Millfield School
Age range
13 - 18
Location
Millfield School, Street, Somerset, BA16 OYD, United Kingdom
Head’s name
Gavin Horgan
Minerva Virtual Academy
Age range
11 - 18
Location
c/o 3 Space International House, London, SW9 7QD
Head’s name
Suzanne Lindley
Monkton Combe School
Age range
13 - 18
Location
Monkton Combe School, Combe Down, Bath, BA2 7ET, United Kingdom
Head’s name
Bradley Salisbury
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