Introduction
One of the most common errors Python developers face — especially beginners — is the ModuleNotFoundError, even after installing a package correctly using pip. This error simply means Python cannot find the module you are trying to import. But the real reason behind this can vary. In many cases, the package is installed, but Python is looking in the wrong place.
What Does ModuleNotFoundError Mean?
Python throws this error when it cannot locate the module you are trying to import. Example:
import pandas
If pandas is not available in the environment Python is using, you will see:
ModuleNotFoundError: No module named 'pandas'
Even if you installed pandas, Python may still not find it due to environment mismatches or incorrect installation.
1. You Installed the Package in a Different Python Environment
This is the most common reason. Your system may have multiple Python versions:
Python 3.8
Python 3.9
Python 3.10
Or you may have multiple tools like:
How to Check Which Python You Are Using
Run:
python --version
Or
python3 --version
How to Check Where pip Is Installing Packages
Run:
pip show package_name
Example:
pip show pandas
This shows the installation path.
Fix
Use the correct pip version for your Python version:
python3 -m pip install package_name
Or for Windows:
py -3.10 -m pip install package_name
2. You Installed the Package Using pip, but Your Editor Uses a Different Interpreter
Tools like VS Code, PyCharm, Jupyter Notebook, and Spyder may use a different Python interpreter from the one where packages were installed.
Fix in VS Code
Fix in PyCharm
A wrong interpreter will always lead to ModuleNotFoundError.
3. You Forgot to Activate Your Virtual Environment
If you installed a package inside a virtual environment but did not activate it, Python outside the environment cannot access that package.
Activate on Windows
venv\Scripts\activate
Activate on macOS/Linux
source venv/bin/activate
After Activation
Run your Python script again.
4. The Package Name You Are Importing Is Incorrect
Sometimes the package installation name and import name are different.
Examples:
Another example:
Fix
Search the correct import name or try:
import package_name
5. The Package Failed to Install Properly
Sometimes installation shows warnings or partial installation.
Fix
Reinstall the package:
pip uninstall package_name
pip install package_name
If it’s a permissions issue:
pip install package_name --user
6. You Are Running the Script From a Directory With the Same Name as a Module
Example:
If your file is named:
pandas.py
And you write:
import pandas
Python will try to import your file instead of the actual package.
Fix
Rename your file.
7. Python Path Issues
Python uses the PYTHONPATH variable to locate modules. If Python paths are broken, imports will fail.
Check Python Path
import sys
print(sys.path)
If the installed package path is missing, Python cannot find it.
Fix
Add the path manually:
import sys
sys.path.append("/path/to/site-packages")
8. Jupyter Notebook Using Different Kernel
Installing a package in terminal does NOT mean Jupyter Notebook can access it.
Fix
Install packages inside Jupyter:
!pip install package_name
Or install into the exact kernel using:
python -m ipykernel install --user
Summary of the Most Reliable Fix
The best universal fix is to install the package using the Python interpreter you are running:
python -m pip install package_name
This ensures pip installs the package in the correct environment.
Conclusion
ModuleNotFoundError in Python usually happens because Python cannot find the package you installed — often due to using the wrong interpreter, wrong environment, or incorrect import name. By checking your Python version, verifying pip installation paths, selecting the right interpreter in your editor, and activating virtual environments, you can fix this error quickly. Once you understand how Python environments and paths work, resolving import issues becomes simple and predicta