diff --git a/docs/dev_environment.md b/docs/dev_environment.md
--- a/docs/dev_environment.md
+++ b/docs/dev_environment.md
@@ -43,6 +43,16 @@
 
 The reason we use both `install` and `upgrade` is that there’s no single Homebrew command equivalent to “install if not installed, and upgrade if already installed”.
 
+## Python 2 (Apple silicon Macs)
+
+For Apple silicon Macs, Python 2.7 is a requirement.
+
+We need Python 2.7 because the `sqlite3` npm package doesn't come with prebuilt ARM64 binaries and requires a native build that depends on Python 2 scripts.
+
+Up until macOS 12.3, Python 2.7 was "included in macOS for compatibility with legacy software." However, if your machine is running macOS 12.3 or later, you'll need to install Python 2.7 manually.
+
+Installing Python 2.x via Homebrew is no longer officially supported. Instead, download and install the Python 2.7.18 64-bit macOS installer from the [Python.org release page](https://www.python.org/downloads/release/python-2718/) and follow the installation steps provided.
+
 ## PHP
 
 [PHP](https://www.php.net) is needed for Arcanist. As of macOS 12 (Monterey), PHP is no longer bundled with the OS and needs to be installed via Homebrew.