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

The rankings: who scores highest

We found published results data for nine Bangkok IB schools. Here they are, 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.

What the numbers tell you

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 genuinely impressive. This 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. For context, 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. It is a strong signal, not a confirmed pattern. 78.5% of that cohort scored 36 or above, which is remarkable, but the question is whether that holds when the cohort doubles or triples.

Bangkok Patana deserves particular attention. It is academically non-selective and runs 128 students through the Diploma. Posting a 35-point average with 99% pass rate and 20% scoring 40+ on a non-selective cohort of that size is arguably more impressive than 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. That is consistency, not luck.

Concordian at 36 is strong, and the trilingual angle (English, Chinese, Thai) makes it unusual. Eleven students hit 40+ in 2024. As far as we can tell, 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?

This is the chart that matters most.

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

A few observations.

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 its results hold up across larger cohorts, it will be the obvious recommendation 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, but it also delivers the highest consistent scores on a large cohort. You get what you pay for.

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. That is roughly 40% less per point than NIST (US$838) or Bangkok Patana (US$800). The trade-off: Ascot's scores are lower, its cohort is smaller, and the campus experience is more modest. But for a family on a tighter budget who still wants the IB pathway, Ascot is the answer the data gives you.

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 does publish detailed results - a 98% pass rate, 16% scoring 40+, and a ten-year track record averaging around 35 - so this is not a data problem. It is an excellent school by most measures, and its American-curriculum base with IB and AP overlays appeals to a different demographic. But 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.

We could not find published IB Diploma results for eight of the 17 schools. That does not mean they don't exist - some may share data in prospectuses, parent briefings, or channels we did not access. 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 appear to publicise their numbers online. Either way, it is a reasonable question to raise during a school visit.

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.

The full-IB pathway is the purist's choice. Students who go through PYP and MYP arrive at the Diploma with years of IB methodology baked in. In theory, this should produce better results. In practice, the data does not support that claim. 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.

The more relevant question is whether the school is selective. NIST and SISB are selective in admissions. Bangkok Patana is not. Concordian is moderately so. When comparing IB averages across schools, selectivity is the hidden variable that explains more of the variance than curriculum structure.

How Bangkok compares globally

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

NIST at 37 is on par with the mid-tier of Singapore's best. It is below Tanglin Trust (39.6) and NPS International (38.9) but above UWCSEA East (36.1). For a city where maximum school fees are roughly half those in Singapore, that is a creditable showing.

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 is unlikely to close that gap soon, and probably should not try. The city'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.

Some of these schools have good reasons for not publishing. 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.

The question to ask on a visit is straightforward: what were your results last year? Any school offering the IB Diploma should be able to tell you the average score, the number of students who sat the exam, and the pass rate. If they seem reluctant, that is worth noting.