diff --git a/mkdocs-dev.yml b/mkdocs-dev.yml
index c165b965..175187a2 100644
--- a/mkdocs-dev.yml
+++ b/mkdocs-dev.yml
@@ -26,6 +26,10 @@ theme:
   palette:
     primary: yellow
     accent: blue
+
+  # Injects depreciation banner 
+  custom_dir: overrides-dev
+
 nav:
   - Features:
     - Getting Started: getting-started/index.md
diff --git a/overrides-dev/main.html b/overrides-dev/main.html
new file mode 100644
index 00000000..2a19a12c
--- /dev/null
+++ b/overrides-dev/main.html
@@ -0,0 +1,9 @@
+{% extends "base.html" %}
+
+{% block header %}
+<!-- Injects depreciation banner over all pages -->
+<div style="background-color: #ffdddd; color: #a00; padding: 1rem; text-align: center; font-weight: bold; font-size: 0.75rem;">
+    ⚠️ This development documentation is deprecated. Please visit <a href="https://zone.pages.cloud.statcan.ca/docs/dev/" style="color: #a00; text-decoration: underline;">The Zone dev documentation site</a>.
+</div>
+{{ super() }}
+{% endblock %}