The American School in London vs Marymount International School London
🇬🇧 London · Side-by-side comparison on verifiable public data.
Both carry a public inspection verdict: The American School in London is Ofsted "Outstanding" and Marymount International School London is Independent Schools Inspectorate (ISI) "Excellent" — a rare pairing where an official quality rating can be compared head-to-head. Curriculum is the core differentiator: The American School in London offers American while Marymount International School London offers IB — the choice should follow the family's target qualification system. One practical difference: Marymount International School London offers boarding while the other is day-only — decisive for families who need a residential option. Verify current fees against each school's own figures (see the table below).
Key Facts
| The American School in London | Marymount International School London | |
|---|---|---|
| Curriculum | American | IB |
| Ages | 4-18 (K1-Grade 12) | 11-18 |
| Languages of instruction | English | English |
| Annual fees | £40,188-£46,428/year (2025-26, incl. VAT; Lower to High School) | Day GBP 39,540/yr; full boarding GBP 66,990/yr (2026-27, incl. VAT) |
| Enrollment | 1,400 | 250 |
| Boarding | Day only | Yes |
| Inspection rating | Ofsted: Outstanding | Independent Schools Inspectorate (ISI): Excellent |
| Accreditations | Middle States Association (MSA), UK Department for Education (DfE), Council of International Schools (CIS), NAIS | Council of International Schools (CIS), Middle States Association of Colleges and Schools, International Baccalaureate Organisation (IBO) |
Strengths
- ✓Ofsted 'Outstanding' overall effectiveness (November 2023), the highest UK inspection grade
- ✓More than 20 Advanced Placement subjects within a coherent American college-prep curriculum
- ✓Multiple recognised accreditations and memberships (MSA, DfE, CIS, NAIS)
- ✓Large, genuinely international community of ~1,400 students from ~70 nationalities
- ✓Experienced, stable faculty with average tenure of about nine years
- ✓ISI 'Excellent' Educational Quality outcome (2022) plus CIS, Middle States and IBO accreditation
- ✓Pioneer IB credentials — adopted the IB as its main curriculum in 1979, among the first in England
- ✓Strong, consistent IB Diploma outcomes (37-point average, 100% pass rate, Class of 2025)
- ✓Small ~250-student, multi-nationality community giving high individual attention
- ✓Established girls' boarding option within a values-led Catholic RSHM ethos
Trade-offs
- !Among the most expensive day schools in London, with mandatory deposit and capital fees on top of tuition
- !No IB and no UK qualifications (GCSE/A level), narrowing exit pathways to the US/AP route
- !High community turnover (~10% leave annually; ~5-year average attendance) can affect peer continuity
- !Day-only: no boarding option for families needing residential places
- !No IB Primary Years Programme — provision starts at age 11, so no early-years or primary pathway
- !Very small enrolment limits breadth of co-curricular and peer cohort scale
- !Premium fees (GBP 39,540 day / up to GBP 66,990 full boarding for 2026-27)
- !Single-curriculum (IB only) with no A-level or alternative-pathway fallback
Best Fit For
- • American and globally mobile families wanting a US-style college-prep pathway in London
- • Students targeting US university admission via AP and SAT
- • Families prioritising a top-rated, fully accredited international school
- • Households settling in northwest or west London near St John's Wood
- • Families seeking an all-girls, values-led Catholic education
- • Internationally mobile families wanting a recognised full IB Diploma pathway
- • Students aged 11+ who thrive in a small, close-knit cohort
- • Families needing girls' boarding (full, weekly or flexi) near London
University Placement
School-reported · not independently verified
School-reported, unverified: ASL describes itself as college-preparatory with students proceeding largely to US and international universities via the AP/SAT route; specific destination data was not located in public sources.
School-reported, unverified: graduates are described as progressing to top-tier universities worldwide, with around a third earning a bilingual IB diploma (Class of 2025).
More Comparisons
Frequently Asked Questions
Should I choose The American School in London or Marymount International School London?
The American School in London is best for: American and globally mobile families wanting a US-style college-prep pathway in London. Marymount International School London is best for: Families seeking an all-girls, values-led Catholic education. The right choice depends on target curriculum, budget, and family priorities — the two are not linearly comparable.
How do fees compare between The American School in London and Marymount International School London?
The American School in London: £40,188-£46,428/year (2025-26, incl. VAT; Lower to High School). Marymount International School London: Day GBP 39,540/yr; full boarding GBP 66,990/yr (2026-27, incl. VAT). Verify against each school's own published fees; some figures are sourced from third-party aggregators.
What curricula do The American School in London and Marymount International School London offer?
The American School in London: American. Marymount International School London: IB. The American School in London inspection: Ofsted "Outstanding". Marymount International School London inspection: Independent Schools Inspectorate (ISI) "Excellent".
Do The American School in London or Marymount International School London offer boarding?
The American School in London: day school only. Marymount International School London: offers boarding.
Questions parents ask
This comparison is BrightKey's independent assessment using verifiable public data only. University-placement figures are school-reported and not independently verified. BrightKey takes no payments from schools. Our method →