diff --git a/axum/CHANGELOG.md b/axum/CHANGELOG.md
index d1a495fd..a02ac1d7 100644
--- a/axum/CHANGELOG.md
+++ b/axum/CHANGELOG.md
@@ -58,6 +58,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **breaking:** `Redirect::found` has been removed ([#800])
 - **breaking:** `AddExtensionLayer` has been removed. Use `Extension` instead. It now implements
   `tower::Layer` ([#807])
+- **breaking:** `AddExtension` has been moved from the root module to `middleware`
 - **fixed:** Set `Allow` header when responding with `405 Method Not Allowed` ([#733])
 - **fixed:** Correctly set the `Content-Length` header for response to `HEAD`
   requests ([#734])
diff --git a/axum/src/add_extension.rs b/axum/src/add_extension.rs
deleted file mode 100644
index 9739eda4..00000000
--- a/axum/src/add_extension.rs
+++ /dev/null
@@ -1,37 +0,0 @@
-// this is vendored from tower-http to reduce public dependencies
-
-use http::Request;
-use std::task::{Context, Poll};
-use tower_service::Service;
-
-/// Middleware for adding some shareable value to [request extensions].
-///
-/// See [Sharing state with handlers](index.html#sharing-state-with-handlers)
-/// for more details.
-///
-/// [request extensions]: https://docs.rs/http/latest/http/struct.Extensions.html
-#[derive(Clone, Copy, Debug)]
-pub struct AddExtension<S, T> {
-    pub(crate) inner: S,
-    pub(crate) value: T,
-}
-
-impl<ResBody, S, T> Service<Request<ResBody>> for AddExtension<S, T>
-where
-    S: Service<Request<ResBody>>,
-    T: Clone + Send + Sync + 'static,
-{
-    type Response = S::Response;
-    type Error = S::Error;
-    type Future = S::Future;
-
-    #[inline]
-    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
-        self.inner.poll_ready(cx)
-    }
-
-    fn call(&mut self, mut req: Request<ResBody>) -> Self::Future {
-        req.extensions_mut().insert(self.value.clone());
-        self.inner.call(req)
-    }
-}
diff --git a/axum/src/extension.rs b/axum/src/extension.rs
index 8ca50d88..ece4d68e 100644
--- a/axum/src/extension.rs
+++ b/axum/src/extension.rs
@@ -1,8 +1,15 @@
-use crate::extract::{rejection::*, FromRequest, RequestParts};
-use crate::response::IntoResponseParts;
+use crate::{
+    extract::{rejection::*, FromRequest, RequestParts},
+    response::IntoResponseParts,
+};
 use async_trait::async_trait;
 use axum_core::response::{IntoResponse, Response, ResponseParts};
-use std::ops::Deref;
+use http::Request;
+use std::{
+    ops::Deref,
+    task::{Context, Poll},
+};
+use tower_service::Service;
 
 /// Extractor and response for extensions.
 ///
@@ -120,12 +127,44 @@ impl<S, T> tower_layer::Layer<S> for Extension<T>
 where
     T: Clone + Send + Sync + 'static,
 {
-    type Service = crate::AddExtension<S, T>;
+    type Service = AddExtension<S, T>;
 
     fn layer(&self, inner: S) -> Self::Service {
-        crate::AddExtension {
+        AddExtension {
             inner,
             value: self.0.clone(),
         }
     }
 }
+
+/// Middleware for adding some shareable value to [request extensions].
+///
+/// See [Sharing state with handlers](index.html#sharing-state-with-handlers)
+/// for more details.
+///
+/// [request extensions]: https://docs.rs/http/latest/http/struct.Extensions.html
+#[derive(Clone, Copy, Debug)]
+pub struct AddExtension<S, T> {
+    pub(crate) inner: S,
+    pub(crate) value: T,
+}
+
+impl<ResBody, S, T> Service<Request<ResBody>> for AddExtension<S, T>
+where
+    S: Service<Request<ResBody>>,
+    T: Clone + Send + Sync + 'static,
+{
+    type Response = S::Response;
+    type Error = S::Error;
+    type Future = S::Future;
+
+    #[inline]
+    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+        self.inner.poll_ready(cx)
+    }
+
+    fn call(&mut self, mut req: Request<ResBody>) -> Self::Future {
+        req.extensions_mut().insert(self.value.clone());
+        self.inner.call(req)
+    }
+}
diff --git a/axum/src/extract/connect_info.rs b/axum/src/extract/connect_info.rs
index e5622031..004e1d83 100644
--- a/axum/src/extract/connect_info.rs
+++ b/axum/src/extract/connect_info.rs
@@ -5,7 +5,7 @@
 //! [`Router::into_make_service_with_connect_info`]: crate::routing::Router::into_make_service_with_connect_info
 
 use super::{Extension, FromRequest, RequestParts};
-use crate::AddExtension;
+use crate::middleware::AddExtension;
 use async_trait::async_trait;
 use hyper::server::conn::AddrStream;
 use std::{
diff --git a/axum/src/lib.rs b/axum/src/lib.rs
index 9f3b02a9..a76a7bad 100644
--- a/axum/src/lib.rs
+++ b/axum/src/lib.rs
@@ -392,7 +392,6 @@
 #[macro_use]
 pub(crate) mod macros;
 
-mod add_extension;
 mod extension;
 #[cfg(feature = "json")]
 mod json;
@@ -409,7 +408,6 @@ pub mod routing;
 #[cfg(test)]
 mod test_helpers;
 
-pub use add_extension::AddExtension;
 #[doc(no_inline)]
 pub use async_trait::async_trait;
 #[cfg(feature = "headers")]
diff --git a/axum/src/middleware/mod.rs b/axum/src/middleware/mod.rs
index 6e3905d9..3273b7d4 100644
--- a/axum/src/middleware/mod.rs
+++ b/axum/src/middleware/mod.rs
@@ -5,6 +5,7 @@
 mod from_fn;
 
 pub use self::from_fn::{from_fn, FromFn, FromFnLayer, Next};
+pub use crate::extension::AddExtension;
 
 pub mod future {
     //! Future types.