Fact check: Which countries have the smallest average penis size according to research?

1. Why the bottom-ranked countries keep changing—methodology drives the headlines

Different studies reach different conclusions because they use incompatible measurement methods and datasets. Some sources use aggregated national data from measurement studies and meta-analyses to compute country averages, producing lists that place Thailand, North Korea, Cambodia, Nepal, and Myanmar among the shortest averages ^{[1] [6]}. Other datasets rely on self-reported surveys collected online, which can inflate or deflate averages depending on sample bias; a British clinic survey ranked Cambodia lowest with 10 cm but noted self-reporting limits ^[3]. Independent compilers using global datasets of varying vintage produce alternative rankings that identify Cambodia or Thailand as the shortest, underlining that method selection—stretched/erect measurement, self-report vs. clinical measurement, and which studies are included—shapes which countries appear smallest ^[5].

2. What the most recent 2025 compilations actually say about the smallest averages

Two recent 2025 compilations converge on East and Southeast Asian countries as the cluster with the smallest reported averages but disagree on the single lowest country. One 2025 compilation reports Thailand as the smallest with an average erect length around 9.43 cm and lists neighboring countries among the shortest ^{[6] [1]}. Another 2025 map-based compilation indicates Cambodia among the smallest with a value near 9.8–10.04 cm and emphasizes regional patterns rather than a single outlier ^{[2] [5]}. These 2025 sources emphasize that regional grouping is more robust than any single-country ranking because cross-study differences shrink when viewing East and Southeast Asia collectively as having lower reported means relative to the global average ^{[1] [2]}.

3. What older and clinical meta-analyses add—and what they don’t say

Systematic reviews and meta-analyses synthesizing measured data often find smaller between-region differences than sensational headlines suggest. A 2025 systematic review of 33 studies reported the largest mean stretched lengths in Americans but did not explicitly list smallest countries, instead noting variability across WHO regions and urging geographic adjustments to standards ^{[4] [7]}. Earlier compilations from 2016–2022 show similar patterns: Cambodia and Thailand frequently appear low in country lists, but meta-analyses caution that the magnitude of national-level differences is modest when only clinically measured data are used, and correlations with height or ethnicity are weak or inconsistent ^{[5] [3]}.

4. How to interpret these findings responsibly—data gaps and confounders

Reported country averages suffer from data sparsity, sampling bias, and methodological inconsistency. Several datasets explicitly note limited or uneven coverage—some countries have few or no clinical measurements, forcing reliance on small samples or self-reports that distort means ^{[2] [3]}. Environmental, hormonal, and developmental factors are mentioned as possible influences, but the evidence is mixed and cannot definitively explain cross-country differences without better longitudinal and population-representative data ^[6]. As a result, rankings should be treated as provisional signals about regional patterns, not definitive biological hierarchies, and policymakers or media should avoid drawing broad cultural or racial conclusions from these provisional lists ^{[4] [3]}.

5. Bottom line—what can be stated with confidence and where uncertainty remains

With available sources, one can confidently state that studies and compilations repeatedly place East and Southeast Asian countries among those with the smallest reported average erect lengths, with Thailand and Cambodia frequently appearing at or near the bottom in multiple datasets ^{[1] [2]}. However, there is no unanimous single-country winner: some 2025 datasets list Thailand as the smallest while others single out Cambodia; systematic reviews emphasize regional rather than national certainty ^{[6] [5] [4]}. The chief takeaway is that reported rankings are method-dependent and sensitive to data quality, so any claim about “which countries have the smallest average” must be accompanied by the dataset, measurement method, and a clear caveat about uncertainty ^{[3] [2]}.