diff --git a/doc/api/buffer.md b/doc/api/buffer.md
index 4c7734e0968a33..e884a7f2320f35 100644
--- a/doc/api/buffer.md
+++ b/doc/api/buffer.md
@@ -872,6 +872,10 @@ The index operator `[index]` can be used to get and set the octet at position
 `index` in `buf`. The values refer to individual bytes, so the legal value
 range is between `0x00` and `0xFF` (hex) or `0` and `255` (decimal).
 
+This operator is inherited from `Uint8Array`, so its behavior on out-of-bounds
+access is the same as `UInt8Array` - that is, getting returns `undefined` and
+setting does nothing.
+
 Example: Copy an ASCII string into a `Buffer`, one byte at a time
 
 ```js