diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index fe983274b5c72..2c786fd511ead 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -2928,6 +2928,8 @@ unsafe impl<#[may_dangle] T, A: Allocator> Drop for Vec<T, A> {
 #[rustc_const_unstable(feature = "const_default_impls", issue = "87864")]
 impl<T> const Default for Vec<T> {
     /// Creates an empty `Vec<T>`.
+    ///
+    /// The vector will not allocate until elements are pushed onto it.
     fn default() -> Vec<T> {
         Vec::new()
     }