IB Results in Bangkok

Bangkok's IB Diploma cohort is the deepest in Southeast Asia outside Singapore. Eleven schools graduated a published Diploma class in the most recent cycle; five of those landed five points or more above the worldwide mean of 30.32.

The headline averages are only part of the read. Cohort size, selectivity, and whether the school runs the full IB continuum or switches into the Diploma at 16 decide how much each number means. A 37 on a 130-strong non-selective cohort is a different result from a 37 on 14 self-selected pioneers. The list below leads with the published average and adds the structural detail behind it.

Ranked by published DP average

The order follows the most recent average each school discloses.

1. Bangkok Patana School. 37 points (2023)

Sukhumvit 105. Founded 1957. 2,300 pupils. The deepest Diploma cohort in Thailand. Patana runs the English National Curriculum from Foundation Stage through IGCSE at Year 11, then converts the senior school to the IB Diploma. The 2023 published cohort averaged 37 points with a 99% pass rate, sitting on 66% A\* or A at IGCSE the year before. Patana is academically non-selective. A 37-point average from a non-selective cohort of this size sits inside the top decile of IB World Schools globally.

2. Concordian International School. 36 points (2024)

Bang Na-Trad, Samut Prakan. Founded 2001. ~900 pupils. The only trilingual full-continuum IB school in Thailand (English, Mandarin, Thai from PYP). CIS and NEASC accredited. The 2024 Diploma cohort averaged 36 points across a moderately selective intake. For families committed to a multilingual IB pathway from age two, alternatives in Bangkok are thin.

3. KIS International School Reignwood Park. 35 points (2024)

Pathum Thani, 35 kilometres north of central Bangkok. Founded 1998 (Reignwood Park campus opened 2019). 800 pupils. CIS accredited. The 2024 Diploma cohort averaged 35 points and generated more than 700 university offers across the year group. Campus scale carries the differentiation: 100 rai (40 acres), outdoor learning, working farm, class sizes of 12 to 16. The cost sits in the commute.

4. St Andrews International School Bangkok (Sukhumvit 71). 34.4 points (2025)

Phra Khanong. Founded 2013. ~2,300 pupils. Operated by Nord Anglia. ENC primary into IB Diploma at sixth form, structurally the same shape as Patana at a lower fee. The 2025 cohort posted a 34.4 average and a 96% pass rate, on 90% IGCSE A\* to C the year before. Sukhumvit 71 is the Nord Anglia campus; a separately operated St Andrews on Sukhumvit 107 carries the same brand without publishing DP averages in the same form.

5. International School Bangkok (ISB). 34 points (2023)

Nichada Thani, Nonthaburi. Founded 1951. Thailand's first international school. ~1,800 pupils. WASC and CIS accredited. American programme PreK to Grade 12 with IB Diploma offered alongside AP in the upper school. The 2023 DP cohort averaged 34 points. ISB's draw is the dual exit: families uncertain between IB and AP get both pathways under one roof, and the upper-school university counselling is built around that fork.

6. Ruamrudee International School. 34 points (97% pass)

Min Buri, eastern Bangkok. Founded 1957 (the same year as Patana). ~1,100 pupils. American programme with a dual IB and AP exit: 97% IB pass rate, 34-point average, 45 AP exams in the most recent published cycle. The 25-kilometre commute east is the trade; the return is a campus larger than most central Bangkok schools combined.

7. Roong Aroon International School. 34 points (2025)

Bangkok. Founded 2019. 65 pupils. The newest entrant, secondary only. IB MYP, DP and CP authorised. The 2025 cohort posted 34 average and 94% pass rate on a small intake. One strong year is not yet a track record.

8. KIS International School Bangkok. 33 points (2022)

Huai Khwang. Founded 1998. ~700 pupils. The most centrally located full-continuum IB school in the city. CIS re-accredited 2023. The 2022 published cohort averaged 33 points with a 90% pass rate. KIS Bangkok shares governance with KIS Reignwood Park on a denser urban campus near Cultural Centre MRT.

NIST publishes a different shape of data

NIST International School (Sukhumvit 31, founded 1992, ~1,800 pupils) publishes the structure of its 2025 cohort rather than a single average score. 110 candidates, 100% pass rate against an 81% global rate, 28% at 40+ against a 9% global rate, two students at the maximum 45 of 45. External league tables that recalculate from those figures put NIST at around a 37-point cohort average for 2025, level with Patana on a continuum-built rather than IGCSE-fed cohort. CIS and NEASC dual-accredited; the only school in Thailand authorised for all four IB programmes (PYP, MYP, DP, CP).

At a glance

NIST reports pass rate, 40+ percentage, top scores, and cohort size in place of a single average. League-table recalculations from those figures land near 37.

How to read these numbers

A published Diploma average answers fewer questions than it looks like. Three structural variables decide how much weight each headline figure carries.

Cohort size. A 37 on 14 students reads on the page identically to a 37 on 130 students. The first describes a self-selected pioneer group; the second describes a school's median graduate.

Selectivity. Bangkok IB schools sit somewhere between Patana's explicit non-selective intake and the tightly screened admission of NIST or Concordian. Selectivity inflates DP averages mechanically. A 35 at a non-selective school often reads as the stronger result.

Pass rate and tail. A 34-point average can sit on a tight cluster of mid-30s scores or a wide spread with a long tail of low ones. NIST's choice to publish the distribution (28% at 40+, 100% pass) instead of an average makes the cohort easier to read. A school posting 35 with 90% pass has a different graduate profile from a school posting 34 with 100% pass.

A complete read combines average, cohort size, pass rate, and selectivity. Schools that publish all four are doing more than the ones that publish only the headline.

Schools with no public DP results

Several Bangkok IB schools are authorised for the Diploma without a public DP average in the latest cycle. The list runs across fee tiers and campus sizes, not only the newer or smaller schools.

• Ascot International School. Describes 2024 results as "above world average" without a number.
• Wells International School. DP authorised; school site emphasises SAT and AP outputs instead.
• Pan-Asia International School. Has produced DP graduates since 2010; cohort averages not published.
• D-PREP International School. DP authorised 2021; cohort averages not published.
• The American School of Bangkok Green Valley. DP authorised, no public average.
• Dulwich College Bangkok. Opened 2026; the 37.5 figure on the public site carries over from the wider Dulwich group, not a Bangkok cohort.
• The Regent's, SISB, Canadian International School of Thailand, Satit Bilingual. Publish other exit data (IGCSE, iPSLE, AP, university placements) but not DP cohort averages.

Authorisation status is verifiable on the IB Organisation public directory. A school running the Diploma can usually answer three questions on a visit without preparation: what is the current cohort size, what was last year's average, and what was the pass rate. A school that struggles to answer those three has told you something.

Related reading

• Best IB schools in Bangkok. The full editorial shortlist with fees and accreditation context.
• Best IB Schools in Bangkok: Results, Fees, Rankings. Value-tier analysis layering fees onto results.
• Best international schools in Bangkok. The city pillar across all curricula.
• What is the IB Diploma?
• IB HL vs SL
• IB vs A-Levels

FAQs

Which Bangkok school has the highest published IB Diploma average?

Bangkok Patana, at 37 points (2023, 99% pass). Patana is academically non-selective and runs one of the largest Diploma cohorts in Thailand. NIST publishes a different shape of data (100% pass, 28% at 40+ on 110 candidates in 2025) that external league tables recalculate to roughly the same average. The two schools are functionally tied at the top.

What is the global IB Diploma average?

30.32 in 2024, per the IB Organisation Statistical Bulletin. Every Bangkok school with a published cohort average clears it. The five strongest sit five to seven points above.

Why does NIST not publish a single average score?

NIST publishes the structure of the cohort: pass rate (100% against a global 81%), percentage at 40+ (28% against a global 9%), top scores (two 45s in 2025), cohort size (110). The distribution is more informative than a single average, which can hide a long tail of low scores.

Is the DP average a good guide to school quality?

It is one input. Cohort size, selectivity, and pass rate decide how much weight to put on it. A 37 on a small selective cohort is a different result from a 37 on a large non-selective one. Schools that publish all four numbers make the result easier to read.

Does my child need to do IB PYP and MYP to do well at IB Diploma?

Not in Bangkok. Patana posts its 37-point average on students who came through IGCSE, not MYP. The case for the full IB continuum is consistency of pedagogy, not stronger Diploma results in aggregate.

How does Bangkok compare to Singapore for IB results?

The top Bangkok schools (Patana 37, NIST equivalent, Concordian 36, KIS Reignwood Park 35) sit in the middle of Singapore's range. Tanglin Trust leads Singapore at around 39.6; UWCSEA Dover at around 36.7. Bangkok's top fees run roughly half of Singapore's.

Sources: published IB Diploma results 2022 to 2025 from individual school websites and annual reports; IB Organisation Statistical Bulletin May 2024 for the 30.32 worldwide average; IB Organisation public school directory for programme authorisations; CIS, NEASC and WASC member registers. Where schools report multiple years, the most recent published figure is used. We work hard to keep these figures accurate. If you spot a number that has moved or a result we have missed, tell us and we will update.