Fixing the Issue: Unable to Import Module 'lambda_function' - Resolving the No Module Named 'lambda_function' Error in AWS Lambda

In this guide, we will discuss the common issue of being unable to import the module lambda_function when working with AWS Lambda. We will provide a step-by-step solution to resolve the "No Module Named 'lambda_function'" error and answer frequently asked questions related to this issue.

Table of Contents

  1. Understanding the Issue
  2. Step-by-Step Solution
  3. FAQ

Understanding the Issue

When working with AWS Lambda functions in Python, you might encounter the following error message:

  "errorMessage": "Unable to import module 'lambda_function': No module named 'lambda_function'",
  "errorType": "Runtime.ImportModuleError"

This error occurs when AWS Lambda is unable to locate the lambda_function module in your deployment package or the handler is not correctly defined.

Understanding AWS Lambda Error Messages

Step-by-Step Solution

To resolve the "No Module Named 'lambda_function'" error, follow these steps:

Step 1: Check Your Deployment Package Structure

Ensure that the deployment package structure is correct. The file should be located at the root level of the deployment package.

└── requirements.txt

Step 2: Review Your Lambda Handler

Check your Lambda function's handler in the AWS Management Console. The handler should be in the format filename.handler_function_name. For example, if your file has a function named my_handler, the handler should be set to lambda_function.my_handler.

AWS Lambda Function Handler in Python

Step 3: Re-Upload Your Deployment Package

After verifying the deployment package structure and Lambda handler, create a new deployment package and upload it to AWS Lambda.

Creating a Deployment Package (Python)

Step 4: Test Your Lambda Function

Once the new deployment package is uploaded, test your Lambda function to see if the error has been resolved.


1. How do I create a deployment package for my Lambda function?

To create a deployment package for your Lambda function, follow the instructions in the Creating a Deployment Package (Python) guide.

2. Can I use a different file name instead of

Yes, you can use any file name for your Lambda function. Just make sure to update the handler in the AWS Management Console to match your file name and handler function name.

3. How do I include third-party libraries in my deployment package?

To include third-party libraries in your deployment package, use the pip command to install the libraries in a folder named package. Then, add your Lambda function code to the package folder and create a ZIP archive of the folder. For more information, follow the instructions in the Creating a Deployment Package (Python) guide.

4. Why am I still getting the "No Module Named 'lambda_function'" error after following these steps?

If the error persists, double-check your deployment package structure, handler settings in the AWS Management Console, and ensure your deployment package does not exceed the maximum unzipped file size of 250 MB. If the issue remains unresolved, check the AWS Lambda Developer Guide and AWS Lambda Forums for additional resources.

5. How do I monitor and troubleshoot my Lambda function?

You can use Amazon CloudWatch Logs and AWS X-Ray to monitor, troubleshoot, and optimize your Lambda function. For more information, refer to the Monitoring and Troubleshooting in AWS Lambda guide.

Great! You’ve successfully signed up.

Welcome back! You've successfully signed in.

You've successfully subscribed to

Success! Check your email for magic link to sign-in.

Success! Your billing info has been updated.

Your billing was not updated.