How to Install `langchain` in Python

v1.2.15 Data & Science Python <4.0.0,>=3.10.0 MIT

Building applications with LLMs through composability

Install pip install langchain

What is langchain?

Building applications with LLMs through composability

Looking for the JS/TS version? Check out LangChain.js.

To help you ship LangChain apps to production faster, check out LangSmith. LangSmith is a unified developer platform for building, testing, and monitoring LLM applications.

LangChain is the easiest way to start building agents and applications powered by LLMs. With under 10 lines of code, you can connect to OpenAI, Anthropic, Google, and more. LangChain provides a pre-built agent architecture and model integrations to help you get started quickly and seamlessly incorporate LLMs into your agents and applications.

PyPI page →

Quick Start

Minimal example to get started with langchain:

import langchain

print(langchain.__version__)

Installation

pip (standard)

pip install langchain

Virtual environment (recommended)

python -m venv venv
source venv/bin/activate   # Windows: venv\Scripts\activate
pip install langchain

pip3

pip3 install langchain

conda

conda install -c conda-forge langchain

Poetry

poetry add langchain

Dependencies

Installing langchain will also install these packages:

langchain-core langgraph pydantic

Verify the Installation

After installing, confirm the package is available:

python -c "import langchain; print(langchain.__version__)"

If this prints a version number, installation succeeded. If you see a ModuleNotFoundError, see the errors section below.

Installation Errors

Common errors when installing langchain with pip.

ModuleNotFoundError: No module named 'langchain'

Cause: The package is not installed in the current Python environment.

Fix: Run pip install langchain. If using a virtual environment, ensure it is activated first.

ModuleNotFoundError: No module named 'langchain' (installed but still failing)

Cause: pip installed the package into a different Python than the one running your script.

Fix: Use python -m pip install langchain to install into the interpreter you are running.

ImportError: cannot import name 'X' from 'langchain'

Cause: The function or class does not exist in the installed version.

Fix: Check the version with pip show langchain and upgrade with pip install --upgrade langchain.

pip: command not found

Cause: pip is not in PATH or Python was not added to PATH during installation.

Fix: Try python -m pip install langchain. On macOS/Linux try pip3.

PermissionError: [Errno 13] Permission denied

Cause: No write access to the system Python package directory.

Fix: Use a virtual environment, or add --user: pip install --user langchain

SSL: CERTIFICATE_VERIFY_FAILED

Cause: pip cannot verify PyPI's SSL certificate — common behind corporate proxies.

Fix: Try: pip install --trusted-host pypi.org --trusted-host files.pythonhosted.org langchain

MemoryError when loading data

Cause: Dataset is too large to fit in RAM.

Fix: Read in chunks, filter columns on load, or consider Polars/Dask for out-of-core processing.

Recent Releases

Version	Released
`1.2.15` latest	2026-04-03
`1.2.14`	2026-03-31
`1.2.13`	2026-03-19
`1.2.12`	2026-03-11
`1.2.11`	2026-03-10

Full release history on PyPI →

Manage langchain

Upgrade to latest version

pip install --upgrade langchain

Install a specific version

pip install langchain==1.2.15

Uninstall

pip uninstall langchain

Check what is installed

pip show langchain

Last updated: 2026-04-11 • Data from PyPI

How to Install langchain in Python