# Fragile Base Class Problem

When a change to a parent class unexpectedly breaks its child classes.

## What is **Fragile Base Class Problem**?

The **fragile base class problem** is when a harmless-looking change to a parent class breaks child classes that relied on how it worked inside. It is one reason to prefer composition.

Level: Master · [More OOP terms at this level](https://www.ask-codey.com/glossary/subjects/oop/master)

Updated: September 27, 2026

Source: https://www.ask-codey.com/glossary/fragile-base-class-problem