diff --git a/cpp/src/arrow/filesystem/s3_internal.h b/cpp/src/arrow/filesystem/s3_internal.h
index 093fdc7ca4577..c6e6349ba2cf8 100644
--- a/cpp/src/arrow/filesystem/s3_internal.h
+++ b/cpp/src/arrow/filesystem/s3_internal.h
@@ -152,10 +152,14 @@ Status ErrorToStatus(const std::string& prefix, const std::string& operation,
   // XXX Handle fine-grained error types
   // See
   // https://sdk.amazonaws.com/cpp/api/LATEST/namespace_aws_1_1_s3.html#ae3f82f8132b619b6e91c88a9f1bde371
-  return Status::IOError(
-      prefix, "AWS Error ",
-      S3ErrorToString(static_cast<Aws::S3::S3Errors>(error.GetErrorType())), " during ",
-      operation, " operation: ", error.GetMessage());
+  auto error_type = static_cast<Aws::S3::S3Errors>(error.GetErrorType());
+  std::stringstream ss;
+  ss << S3ErrorToString(error_type);
+  if (error_type == Aws::S3::S3Errors::UNKNOWN) {
+    ss << " (HTTP status " << static_cast<int>(error.GetResponseCode()) << ")";
+  }
+  return Status::IOError(prefix, "AWS Error ", ss.str(), " during ", operation,
+                         " operation: ", error.GetMessage());
 }
 
 template <typename ErrorType, typename... Args>