How to Install requirements.txt in Python: A Complete Guide

Managing Python project dependencies becomes significantly easier once you understand requirements.txt — a plain-text file that lists every package your project needs to run. Whether you're setting up a colleague's project, deploying to a server, or recreating a development environment, knowing how to install from this file is a foundational Python skill.

What Is requirements.txt?

A requirements.txt file is a simple list of Python packages, one per line, that a project depends on. It typically looks something like this:

Each line can specify an exact version (using ==), a minimum version (using >=), or no version at all — leaving pip to install the latest available release. This file is the standard way Python developers communicate dependencies across machines, teams, and environments.

The Core Command: pip install -r

The primary method for installing all packages listed in a requirements.txt file uses pip, Python's built-in package manager. The command is: