diff --git a/build_rust.py b/build_rust.py
index 5c5e557ee..662474dcb 100644
--- a/build_rust.py
+++ b/build_rust.py
@@ -15,6 +15,9 @@ def build(setup_kwargs: Dict[str, Any]) -> None:
         path=cargo_toml_path,
         binding=Binding.PyO3,
         py_limited_api=True,
+        # We force always building in release mode, as we can't tell the
+        # difference between using `poetry` in development vs production.
+        debug=False,
     )
     setup_kwargs.setdefault("rust_extensions", []).append(extension)
     setup_kwargs["zip_safe"] = False
diff --git a/changelog.d/14009.bugfix b/changelog.d/14009.bugfix
new file mode 100644
index 000000000..5f85fee96
--- /dev/null
+++ b/changelog.d/14009.bugfix
@@ -0,0 +1 @@
+Fix bug where Rust extension wasn't built in `release` mode when using `poetry install`.