International School of London (ISL London)
🇬🇧 London · Founded 1972 · IB · Ages 3-18
A long-established, non-selective full-IB-continuum international school in West London whose genuine differentiator is an unusually deep mother-tongue and EAL programme — 24 home languages taught as part of the curriculum and a majority of leavers earning the bilingual IB Diploma.
Curricula
IB
Age range
3-18
Languages of instruction
English
Annual fees
SGD £24,630–£39,640/year (2026/2027, ages 3–17; figures incl. VAT where applicable)
Boarding
No (day school)
IB authorised
PYP, MYP, DP
Ofsted 2023
Good
Accreditations
Council of International Schools (CIS), International Baccalaureate Organization (IBO)
Tier Profile
We only tier dimensions backed by a public inspection verdict or verifiable accreditation. Other dimensions show a data flag — never a guessed score.
BrightKey's Assessment
The International School of London (ISL London) is one of the United Kingdom's oldest international schools, founded in 1972 and among the first in the country to offer the International Baccalaureate. It runs the full IB continuum — Primary Years Programme, Middle Years Programme and Diploma Programme — for a non-selective, co-educational community of students aged 3 to 18 across a Chiswick campus (Primary and Middle School, 139 Gunnersbury Avenue, W3 8LG) and a separate Ealing-based IB Diploma College (15 Gunnersbury Avenue, W5 3XD).
The school's signature strength is language. Its own School Profile reports 24 home languages taught as part of the curriculum, alongside an 'English at ISL' / EAL pathway, with the explicit aim of developing and maintaining each student's mother tongue while they acquire English. This shows up in results: the school reports that roughly half of leavers graduate with a bilingual IB Diploma, far above the IB world rate, and a five-year average Diploma score of 34 points against a global average near 30.
On the verifiable inspection and accreditation evidence, ISL London is accredited by the Council of International Schools (CIS) and is an authorised IB World School (code 000057). As an independent school registered with the UK Department for Education, it is inspected by Ofsted, whose November 2023 report judged 'overall effectiveness' as 'Good' — a solid, mid-upper band rather than the top 'Outstanding' rating.
The school is a day school (no boarding) and explicitly non-selective on admission, which — combined with its language model — makes it well suited to internationally mobile, multilingual families who want their child to keep their first language while following a globally portable curriculum. Fees for 2026/2027 run from £24,630 in the early years to £39,640 in the final Diploma years.
Why These Ratings?
Inspection & AccreditationA — Excellent
Ofsted-inspected with an 'overall effectiveness' judgement of 'Good' at the November 2023 inspection (not the top 'Outstanding' band), so it sits at A rather than S. The school is also accredited by the Council of International Schools (CIS) and is a long-standing IB World School (school code 000057), but the verbatim inspectorate band is what sets the tier.
Strengths & Trade-offs
Strengths
- Exceptional mother-tongue programme — 24 home languages taught as part of the curriculum, a genuine sector outlier
- Strong bilingual outcomes — about half of leavers earn the bilingual IB Diploma, well above the IB world average
- Full IB continuum (PYP, MYP, DP) under one provider, giving age-3-to-18 curricular coherence
- Long pedigree and accreditation — founded 1972, CIS-accredited, authorised IB World School (code 000057)
- Genuinely international and non-selective — 54 student nationalities across the IB programmes, open admissions
Trade-offs
- Ofsted rating is 'Good', not 'Outstanding', so it is not in the top inspection band
- High fees (up to £39,640/year) place it among the more expensive London options
- Split-site model (Chiswick primary/middle, Ealing Diploma College) rather than a single campus
- No British (A-level/GCSE) or American track for families wanting a non-IB pathway
Is It Right For You?
Best For
- ✓Internationally mobile families wanting a globally portable IB pathway
- ✓Multilingual households wanting their child's mother tongue actively maintained
- ✓Students who will sit the bilingual IB Diploma
- ✓Families seeking a non-selective school with a strong EAL on-ramp into English
Not Ideal For
- ✕Families set on a British curriculum (GCSE/A-level) or American diploma
- ✕Households needing boarding provision
- ✕Those prioritising a single all-through campus over a split-site model
- ✕Budget-constrained families given fees up to ~£39,640/year
Curriculum
Full IB continuum only: PYP (primary), MYP (middle) and the Diploma Programme at the Ealing-based IB Diploma College (equivalent to UK Sixth Form / Grades 11–12). Most students take the bilingual IB Diploma; core elements include Theory of Knowledge, the Extended Essay and CAS. The school also awards its own High School Diploma and Advanced High School Diploma alongside the IB.
Fees
Published 2026/2027 annual tuition ranges from £24,630 (Early Childhood 1, age 3) to £39,640 (Grades 11–12, ages 16–17), inclusive of VAT where applicable; the school states fees cover loan of books for the year and an initial sports uniform. Always confirm current fees, registration and deposit charges directly with admissions.
Admissions
Admission is non-selective and co-educational across ages 3–18; the school's EAL / 'English at ISL' provision is designed to bring in students who are still acquiring English while maintaining their home language. Confirm assessment, English-support placement and entry points directly with the admissions office.
Campus Life
Two West London sites: Primary and Middle School at 139 Gunnersbury Avenue, Chiswick (W3 8LG), and the IB Diploma College at 15 Gunnersbury Avenue, Ealing (W5 3XD). The community spans 54 student nationalities and 40 staff nationalities across the IB programmes, with multilingualism woven through daily school life via the home-languages programme. It is a day school with no boarding.
University Placement
School-reported · not independently verified
School-reported, unverified: published higher-education destinations (2012–2025 dataset) include King's College London, UCL, Imperial College London, Warwick, Edinburgh, Manchester and Bristol in the UK, plus international destinations such as Bocconi, Sciences Po, McGill, University of Toronto, University of Chicago and Keio University.
Sources
Every verifiable fact carries a public source — verify it yourself.
- ISL London — official website · 2026-06
- ISL London — School Profile 2024/2025 (founding, IB programmes, 34 avg, 24 home languages, 54 nationalities, CIS, Ofsted, IB code 000057) · 2026-06
- ISL London — Tuition fees 2026/2027 · 2026-06
- IB World School directory — ISL London (code 000057) · 2026-06
- Ofsted inspection report — International School of London (W3 8LG), inspected 22–24 Nov 2023, 'Good' · 2026-06
- ISL Group — history (founded 1972) · 2026-06
📬 Get notified when we publish new university guides
Compare International School of London with
Side-by-side: curriculum, fees, accreditation, honest trade-offs