diff --git a/docs/reference-guides/block-api/block-bindings.md b/docs/reference-guides/block-api/block-bindings.md
index c26ade45e8b5e..d5610af9a4b5a 100644
--- a/docs/reference-guides/block-api/block-bindings.md
+++ b/docs/reference-guides/block-api/block-bindings.md
@@ -20,6 +20,9 @@ An example could be connecting an Image block `url` attribute to a function that
 } -->
 ```
 
+<div class="callout callout-alert">
+<strong>Note:</strong> Post meta keys that begin with an underscore (e.g. `_example_key`) are protected and cannot be used with Block Bindings. Additionally, post meta must be registered with `show_in_rest = true` to be available through the Block Bindings API.
+</div>
 
 ## Compatible blocks and their attributes