diff --git a/pyproject.toml b/pyproject.toml
index 6898b3f64f9c..41f94e645f5b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -47,6 +47,7 @@ include = [
     { path = "rust-toolchain.toml", format = ["sdist", "wheel"] },
     # this one isn't discovered by maturin because it's behind a feature flag
     { path = "crates/uv-production-memory-allocator/**/*", format = ["sdist", "wheel"] },
+    { path = "crates/uv-production-flate2-backend/**/*", format = ["sdist", "wheel"] },
     { path = "LICENSE-APACHE", format = "sdist" },
     { path = "LICENSE-MIT", format = "sdist" },
 ]