diff --git a/src/source_distribution.rs b/src/source_distribution.rs
index 6d00eadd4..f9bd03eba 100644
--- a/src/source_distribution.rs
+++ b/src/source_distribution.rs
@@ -511,6 +511,7 @@ pub fn source_distribution(
                 debug!("Ignoring {}", source.display());
                 continue;
             }
+            let source = fs::canonicalize(source)?;
             let target = root_dir.join(source.strip_prefix(&pyproject_dir)?);
             if source.is_dir() {
                 writer.add_directory(target)?;