Bangkok: Best IB Schools (Results, Fees, Rankings)

The rankings: who scores highest

Nine Bangkok IB schools publish recent results. Ranked by most recent average IB Diploma score.

A note on ISB (International School Bangkok): it is Thailand's first international school (est. 1951), with approximately 1,800 students from 60+ nationalities. Its 2026/2027 fees are ฿659,000-฿1,197,000/year (approximately US$19,000-US$34,000). ISB is listed on the International Schools Guide. Fee data drawn from ISB's published schedule.

NIST is the benchmark. A 37-point average on a cohort of 110 students, with a 100% pass rate and two perfect 45s in 2025, is not a small, cherry-picked group: NIST runs one of the largest IB cohorts in Thailand. It ranks 73rd globally on the ib-schools.com league table (2025 data) and is the only Bangkok school in the top 100. That places it alongside UWCSEA East in Singapore and Dulwich College Shanghai Pudong.

SISB sits at the top of the table with a 37.4 average, but this was its first-ever IB cohort in 2022 with roughly 14 students. A small, self-selected pioneer group tends to skew high. 78.5% of that cohort scored 36 or above, which is remarkable, but unproven across larger cohorts.

Bangkok Patana is academically non-selective and runs 128 students through the Diploma. A 35-point average with 99% pass rate and 20% scoring 40+ on a non-selective cohort of that size beats higher averages at selective schools with smaller groups. For over a decade, Patana has maintained an average five or more points above the global average.

Concordian at 36 is strong, and the trilingual model (English, Chinese, Thai) is unusual: eleven students hit 40+ in 2024. It is the only fully trilingual IB school in Thailand.

KIS has a solid track record. Its five-year average sits at 34.5, and it posted 35 in 2025. In 2025, 84% of its Grade 12 students took the full Diploma, which suggests it is not gaming numbers by steering weaker students away from the full programme.

Results vs fees: where is the value?

The scatter plot maps each school's highest annual fee against its most recent average IB score. Schools in the top-left deliver the most IB points per dollar. Schools in the bottom-right charge premium prices for middling results.

SISB is the standout on value positioning. A 37.4 average at US$23,000 per year places it well above the trend line. If results hold up across larger cohorts, it will be the obvious pick for families who want top results without top-tier fees.

NIST earns its price tag. At US$31,000 per year, it is the most expensive IB school in Bangkok, and it also delivers the highest consistent scores on a large cohort.

Ascot is the value play. At US$17,000 for the oldest year groups and a 33.7 average, it costs US$504 per IB point, roughly 40% less per point than NIST (US$838) or Bangkok Patana (US$800). Ascot's scores are lower, its cohort is smaller, and the campus experience is more modest. For a family on a tighter budget who still wants the IB pathway, Ascot is the answer the data gives.

ISB is an outlier in the other direction. At approximately US$34,000 per year for the oldest year groups and a 34-point average, it sits well below the trend line. ISB publishes detailed results: a 98% pass rate, 16% scoring 40+, and a ten-year track record averaging around 35. Its American-curriculum base with IB and AP overlays appeals to a different demographic. On a pure results-per-dollar basis, it is the most expensive IB point in Bangkok.

All 17 Bangkok IB schools: fee comparison

Not all of these schools appear to publish IB results. Several are newer programmes, have small cohorts, or have chosen not to share publicly. The fee data below covers all 17 IB-offering schools listed on the International Schools Guide.

Eight of the 17 schools do not publish IB Diploma results online. That does not mean they don't exist; some share data in prospectuses or parent briefings. Some have genuinely small or new programmes (D-PREP was only authorised in 2021). Others, like Wells and Pan-Asia, are well-established but do not publicise their numbers online.

Full IB vs IB Diploma: does it matter?

Five Bangkok schools run the full IB continuum: PYP (Primary Years Programme), MYP (Middle Years Programme), and DP (Diploma Programme). These are NIST, KIS, Concordian, Ascot, and Wells. The rest offer only the two-year IB Diploma in the final years, typically layered onto a British or American curriculum.

Students who go through PYP and MYP arrive at the Diploma with years of IB methodology baked in. The data does not show this produces better results. Bangkok Patana (IB/British hybrid) posts a 35 average; Ascot (full IB) posts a 33.7. Concordian (full IB) posts a 36; St Andrews (IB/British) posts a 33. The curriculum pathway matters less than teaching quality, student cohort, and institutional culture.

Selectivity explains more of the variance. NIST and SISB are selective in admissions. Bangkok Patana is not. Concordian is moderately so.

How Bangkok compares globally

Bangkok's top IB schools are competitive regionally but do not crack the highest global tiers.

NIST at 37 sits in the mid-tier of Singapore's best: below Tanglin Trust (39.6) and NPS International (38.9), above UWCSEA East (36.1). Bangkok's maximum school fees are roughly half Singapore's.

The gap between Bangkok's best (37) and the global elite (43+) is significant. Schools scoring consistently above 40 tend to be highly selective, often boarding, and frequently in markets with deeper pools of academically ambitious families. Bangkok's strength is breadth and value, not ultra-selectivity.

The schools that don't publish results

We could not find publicly accessible IB results data for Wells, Pan-Asia, Canadian IST, Satit Bilingual, Roong Aroon, ASB Green Valley, St Andrews Sukhumvit 107, or D-PREP. This covers a fee range from US$5,000 to US$22,000 per year, so it is not exclusively a budget-school phenomenon.

D-PREP is a new programme with only a few graduating cohorts. Canadian IST and Satit Bilingual operate at the budget end and may not yet have the critical mass of IB students to make averages meaningful. Wells has three campuses and a long history but has focused on AP credentials more than IB marketing.

Any school offering the IB Diploma should be able to tell a visiting parent the average score, the number of students who sat the exam, and the pass rate. Reluctance to share those numbers is itself information.

FAQs

What is the highest-scoring IB school in Bangkok? NIST International School, with a 37-point average (Class of 2025) on a cohort of approximately 110 students and a 100% pass rate. SISB posted a higher average (37.4) but on its first cohort of roughly 14 students in 2022, which is too small to draw firm conclusions.

How much do IB schools in Bangkok cost? Annual fees range from US$5,000 (Canadian International School of Thailand) to US$31,000 (NIST) for the oldest year groups. The median for schools with published IB results is around US$24,000-US$28,000. Entry-level fees are lower, typically US$8,000-US$18,000. Fee data from the International Schools Guide.

Which Bangkok IB school offers the best value? On a cost-per-IB-point basis, Ascot International School (US$504 per point) and SISB (US$615 per point) are the strongest performers. Ascot charges US$17,000 per year for the oldest year groups and averages 33.7; SISB charges US$23,000 and averaged 37.4 on its first cohort. Ruamrudee (US$647 per point) is the best value among the mid-range schools with a 34 average at US$22,000.

Is Bangkok Patana academically selective? No. Bangkok Patana is explicitly non-selective and runs one of the largest IB cohorts in Bangkok (128 students in 2025). Its 35-point average and 99% pass rate on a non-selective intake makes it one of the more creditable IB results in the city.

How does Bangkok compare to Singapore for IB results? Bangkok's top school (NIST, 37 avg) sits between Singapore's mid and upper tier. Tanglin Trust leads Singapore at 39.6, and NPS International at 38.9. NIST is above UWCSEA East (36.1). Bangkok's maximum IB fees (US$31,000) are roughly half Singapore's top end (US$39,000+), making it significantly better value per IB point.

How we compiled this data: Fee data covers 17 Bangkok IB schools with published fee ranges, sourced from the International Schools Guide. IB results data is sourced from school websites, social media announcements, IBO statistical bulletins, and the ib-schools.com global league table. Where schools report multiple years of results, the most recent published figure is used. ISB (International School Bangkok) is included for context but is not listed on the International Schools Guide; its fee data is approximate. "Cost per IB point" divides the highest annual fee by the average IB Diploma score. All figures are approximate USD equivalents. Fees correct as of March 2026. Exchange rate: THB 35.6 = US$1 (March 2026).

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