diff --git a/crates/build-rs-test-lib/build.rs b/crates/build-rs-test-lib/build.rs
index a6065ef03..1167a3490 100644
--- a/crates/build-rs-test-lib/build.rs
+++ b/crates/build-rs-test-lib/build.rs
@@ -47,6 +47,7 @@ fn smoke_test_inputs() {
     dbg!(cargo_encoded_rustflags());
     dbg!(cargo_feature("unstable"));
     dbg!(cargo_manifest_dir());
+    dbg!(cargo_manifest_path());
     dbg!(cargo_manifest_links());
     dbg!(cargo_pkg_authors());
     dbg!(cargo_pkg_description());
diff --git a/crates/build-rs/src/input.rs b/crates/build-rs/src/input.rs
index 94d19302a..93faf1400 100644
--- a/crates/build-rs/src/input.rs
+++ b/crates/build-rs/src/input.rs
@@ -29,6 +29,18 @@ pub fn cargo_manifest_dir() -> PathBuf {
     to_path(var_or_panic("CARGO_MANIFEST_DIR"))
 }
 
+/// The path to the manifest of your package.
+#[track_caller]
+pub fn cargo_manifest_path() -> PathBuf {
+    var_os("CARGO_MANIFEST_PATH")
+        .map(to_path)
+        .unwrap_or_else(|| {
+            let mut path = cargo_manifest_dir();
+            path.push("Cargo.toml");
+            path
+        })
+}
+
 /// The manifest `links` value.
 #[track_caller]
 pub fn cargo_manifest_links() -> Option<String> {