diff --git a/src/tuples-and-arrays/arrays.md b/src/tuples-and-arrays/arrays.md
index f3c982e7..7ed57288 100644
--- a/src/tuples-and-arrays/arrays.md
+++ b/src/tuples-and-arrays/arrays.md
@@ -65,4 +65,9 @@ fn main() {
 - Adding `#`, eg `{a:#?}`, invokes a "pretty printing" format, which can be
   easier to read.
 
+- Arrays are not heap-allocated. They are regular values with a fixed size known
+  at compile time, meaning they go on the stack. This can be different from what
+  students expect if they come from a garbage collected language, where arrays
+  may be heap allocated by default.
+
 </details>