| School | HMC Division | Membership | Location | Age Range |
| Giggleswick School | North East (UK) | British Isles | Settle, United Kingdom | 2 - 18 |
| Glenalmond College | Scottish (UK) | British Isles | Glenalmond, United Kingdom | 12 - 18 |
| Godolphin School | South Central (UK) | British Isles | Salisbury, United Kingdom | 3 - 18 |
| Gordon’s School | South Central (UK) | Associate | Woking, United Kingdom | 11 - 18 |
| Gordonstoun | Scottish (UK) | British Isles | Elgin, United Kingdom | 5 - 18 |
| Gresham’s School | East (UK) | British Isles | Holt, United Kingdom | 2 - 18 |
| Guildford High School | South Central (UK) | British Isles | Guildford, United Kingdom | 4 - 18 |
| Haberdashers’ Boys’ School | London (UK) | British Isles | Borehamwood, United Kingdom | 5 - 18 |
| Haileybury | London (UK) | British Isles | Hertford, United Kingdom | 11 - 18 |
| Halliford School | London (UK) | British Isles | Shepperton, Surrey, United Kingdom | 11 - 18 |
| Hampton School | London (UK) | British Isles | Hampton, Richmond upon Thames, United Kingdom | 3 - 18 |
| Harrow International School, Bangkok | International | International | Bangkok, Thailand | 2 - 18 |
| Harrow International School, Hong Kong | International | International | Tuen Mun, Hong Kong | 3 - 18 |
| Harrow School | London (UK) | British Isles | Harrow, London, United Kingdom | 13 - 18 |
| Hereford Cathedral School | West (UK) | British Isles | Hereford, United Kingdom | 3 - 18 |
| High School of Dundee | Scottish (UK) | British Isles | Dundee, United Kingdom | 3 - 18 |
| High School of Glasgow | Scottish (UK) | British Isles | Glasgow, United Kingdom | 3 - 18 |
| Highgate School | London (UK) | British Isles | Haringey, London, United Kingdom | 3 - 18 |
| Hill House School | North East (UK) | British Isles | Doncaster, United Kingdom | 4 - 18 |
| Howell’s School, Llandaff | South West (UK) | British Isles | Cardiff, United Kingdom | 3 - 18 |
| Hurstpierpoint College | South East (UK) | British Isles | Hurstpierpoint, United Kingdom | 4 - 18 |
| Hutchesons’ Grammar School | Scottish (UK) | British Isles | Glasgow, United Kingdom | 3 - 18 |
| Hymers College | North East (UK) | British Isles | Hull, United Kingdom | 3 - 18 |
| Ibstock Place School | London (UK) | British Isles | Roehampton, London, United Kingdom | 4 - 18 |
| Immanuel College | London (UK) | British Isles | Bushey, Herts, United Kingdom | 4 - 18 |
| Ipswich School | East (UK) | British Isles | Ipswich, United Kingdom | 3 - 18 |
| James Allen’s Girls’ School | London (UK) | British Isles | Dulwich, London, United Kingdom | 4 - 18 |
| Jerudong International School | International | International | Bandar Seri Begawan, Brunei Darussalam | 2 - 18 |
| JESS, Dubai | International | International | Dubai, United Arab Emirates | 3 - 18 |
| John Lyon School | London (UK) | British Isles | Harrow, London, United Kingdom | 3 - 18 |
| Jumeirah College, Dubai | International | International | Dubai, United Arab Emirates | 11 - 18 |
| Kellett School, The British International School in Hong Kong | International | International | Kowloon Bay, Hong Kong | 4 - 18 |
| Kelvinside Academy | Scottish (UK) | British Isles | Glasgow, United Kingdom | 3 - 18 |
| Kent College Pembury | South East (UK) | British Isles | Tunbridge Wells, United Kingdom` | 3 - 18 |
| Kent College, Canterbury | South East (UK) | British Isles | Canterbury, United Kingdom | 11 - 18 |
| Kimbolton School | East (UK) | British Isles | Huntingdon, United Kingdom | 4 - 18 |
Giggleswick School
Age range
2 - 18
Location
Giggleswick, Settle, North Yorkshire, BD24 0DE, United Kingdom
Head’s name
Sam Hart
Glenalmond College
Age range
12 - 18
Location
Warden's House, Glenalmond, Perthshire, Scotland, PH1 3RY, United Kingdom
Head’s name
To be confirmed
Godolphin School
Age range
3 - 18
Location
Milford Hill, Salisbury, SP1 2RA, United Kingdom
Head’s name
To be confirmed
Gordon’s School
Age range
11 - 18
Location
West End, Woking, Surrey, GU24 9PT, United Kingdom
Head’s name
Andrew Moss
Gordonstoun
Age range
5 - 18
Location
Gordonstoun, Elgin, Moray, Scotland, IV30 5RF, United Kingdom
Head’s name
Lisa Kerr
Gresham’s School
Age range
2 - 18
Location
Gresham's School, Holt, Norfolk, NR25 6EA, United Kingdom
Head’s name
Douglas Robb
Guildford High School
Age range
4 - 18
Location
London Road, Guildford, Surrey, GU1 1SJ, United Kingdom
Head’s name
Karen Laurie
Haberdashers’ Boys’ School
Age range
5 - 18
Location
Butterfly Lane, Elstree, Borehamwood, Herts, WD6 3AF, United Kingdom
Head’s name
Gus Lock
Haileybury
Age range
11 - 18
Location
Haileybury, Hertford, SG13 7NU, United Kingdom
Head’s name
Martin Collier
Halliford School
Age range
11 - 18
Location
Russell Road, Shepperton, Middlesex, TW17 9HX, United Kingdom
Head’s name
James Davies
Hampton School
Age range
3 - 18
Location
Hampton School, Hampton, Middlesex, TW12 3HD, United Kingdom
Head’s name
Kevin Knibbs
Harrow International School, Bangkok
Age range
2 - 18
Location
45 Soi Kosumruamchai 14, Kosumruamchai Rd, Don Mueang Subdistrict, Don Mueang District, Bangkok 10210, Thailand
Head’s name
James Murphy-O'Connor
Harrow International School, Hong Kong
Age range
3 - 18
Location
38 Tsing Ying Road, Tuen Mun, Hong Kong
Head’s name
Ann Haydon
Harrow School
Age range
13 - 18
Location
5 High Street, Harrow, Middlesex, HA1 3HP, United Kingdom
Head’s name
Alastair Land
Hereford Cathedral School
Age range
3 - 18
Location
Old Deanery, Hereford, Herefordshire, HR1 2NG, United Kingdom
Head’s name
Michael Gray
High School of Dundee
Age range
3 - 18
Location
Euclid Crescent, Dundee, Tayside, Scotland, DD1 1HU, United Kingdom
Head’s name
Lise Hudson
High School of Glasgow
Age range
3 - 18
Location
27 Ledcameroch Road, Bearsden, Glasgow, Scotland, G61 4AE, United Kingdom
Head’s name
John O'Neill
Highgate School
Age range
3 - 18
Location
North Road, Haringey, London, N6 4AY, United Kingdom
Head’s name
Adam Pettitt
Hill House School
Age range
4 - 18
Location
Sixth Avenue, Doncaster, South Yorkshire, DN9 3GG, United Kingdom
Head’s name
David Holland
Howell’s School, Llandaff
Age range
3 - 18
Location
Cardiff Road, Cardiff, Wales, CF5 2YD, United Kingdom
Head’s name
Sally Davis
Hurstpierpoint College
Age range
4 - 18
Location
College Lane, Hurstpierpoint, West Sussex, BN6 9JS, United Kingdom
Head’s name
Tim Manly
Hutchesons’ Grammar School
Age range
3 - 18
Location
21 Beaton Road, Glasgow, Scotland, G41 4NW, United Kingdom
Head’s name
Mike Martin
Hymers College
Age range
3 - 18
Location
Hymers Avenue, Hull, HU3 1LN, United Kingdom
Head’s name
Justin Stanley
Ibstock Place School
Age range
4 - 18
Location
Clarence Lane, Roehampton, London, SW15 5PY, United Kingdom
Head’s name
Christopher Wolsey
Immanuel College
Age range
4 - 18
Location
Elstree Road, Bushey, Herts, WD23 4EB, United Kingdom
Head’s name
Millan Sachania
Ipswich School
Age range
3 - 18
Location
25 Henley Road, Ipswich, Suffolk, IP1 3SG, United Kingdom
Head’s name
Nicholas Weaver
James Allen’s Girls’ School
Age range
4 - 18
Location
144 East Dulwich Grove, London, SE22 8TE, United Kingdom
Head’s name
Alex Hutchinson
Jerudong International School
Age range
2 - 18
Location
Jalan Universiti, Bandar Seri Begawan BE 2119, Brunei Darussalam
Head’s name
Nicholas Sheehan
JESS, Dubai
Age range
3 - 18
Location
28 8 B St, Al Safa, Al Safa 1, Dubai, United Arab Emirates
Head’s name
Shane O'Brien
John Lyon School
Age range
3 - 18
Location
Middle Road, Harrow-on-the-Hill, HA2 0HN, United Kingdom
Head’s name
Rose Hardy
Jumeirah College, Dubai
Age range
11 - 18
Location
Al Wasl Road - Dubai - United Arab Emirates
Head’s name
Nick Brain
Kellett School, The British International School in Hong Kong
Age range
4 - 18
Location
7 Lam Hing Street, Kowloon Bay, Hong Kong
Head’s name
Diana Vernon
Kelvinside Academy
Age range
3 - 18
Location
33 Kirklee Road, Glasgow, Scotland, G12 0SW, United Kingdom
Head’s name
Daniel Wyatt
Kent College Pembury
Age range
3 - 18
Location
Old Church Road, Tunbridge Wells, Kent, TN2 4AX, United Kingdom`
Head’s name
Katrina Handford
Kent College, Canterbury
Age range
11 - 18
Location
Kent College, Canterbury, CT2 9DT, United Kingdom
Head’s name
Mark Turnbull
Kimbolton School
Age range
4 - 18
Location
Kimbolton, Huntingdon, Cambridgeshire, PE28 OEA, United Kingdom
Head’s name
Will Chuter