diff --git a/docs/internals/contributing/writing-code/unit-tests.txt b/docs/internals/contributing/writing-code/unit-tests.txt
index 1c382c79cd0..f686ae6fe69 100644
--- a/docs/internals/contributing/writing-code/unit-tests.txt
+++ b/docs/internals/contributing/writing-code/unit-tests.txt
@@ -259,6 +259,15 @@ You can resolve this on Debian-based systems, for example, by running::
     $ apt-get install locales
     $ dpkg-reconfigure locales
 
+You can resolve this for macOS systems by configuring your shell's locale::
+
+    $ export LANG="en_US.UTF-8"
+    $ export LC_ALL="en_US.UTF-8"
+
+Run the ``locale`` command to confirm the change. Optionally, add those export
+commands to your shell's startup file (e.g. ``~/.bashrc`` for Bash) to avoid
+having to retype them.
+
 Tests that only fail in combination
 -----------------------------------
 
diff --git a/docs/spelling_wordlist b/docs/spelling_wordlist
index 3eab2ce799e..a8b0184d709 100644
--- a/docs/spelling_wordlist
+++ b/docs/spelling_wordlist
@@ -451,6 +451,7 @@ lowercasing
 lt
 lte
 Luhn
+macOS
 Magee
 makemessages
 makemigrations