---
title: "Population Pyramid: Age-Sex Structure Explained"
description: "A population pyramid charts a country's age-sex structure to reveal growth, decline, or ageing. Learn its three classic shapes and why demographers rely on it."
url: "https://modeldiplomat.com/learn/glossary/population-pyramid"
---

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Model Diplomat Research Team · Last reviewed June 22, 2026

TL;DR

- A population pyramid is a graphical representation of a population's age and sex composition, displaying age cohorts horizontally with males and females on opposite sides.
- What are the three main types of population pyramid?
- How does a population pyramid differ from the demographic transition model?
- Why is India's population pyramid significant for policymakers?
- What distortions can make a population pyramid misleading?

[Civil Service & Diplomatic Exams](https://modeldiplomat.com/learn/civil-services/glossary)Updated June 22, 2026

A population pyramid is a graphical representation of a population's age and sex composition, displaying age cohorts horizontally with males and females on opposite sides.

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Japan's Statistics Bureau, in its 2023 population estimates, published a constrictive age-sex pyramid showing the over-65 cohort at 29.1 percent, the highest share recorded by any nation, underscoring the country's accelerating demographic ageing.

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