diff --git a/cpp/src/arrow/flight/serialization_internal.cc b/cpp/src/arrow/flight/serialization_internal.cc
index fb890d926d2..cf5f4140c37 100644
--- a/cpp/src/arrow/flight/serialization_internal.cc
+++ b/cpp/src/arrow/flight/serialization_internal.cc
@@ -374,7 +374,13 @@ grpc::Status FlightDataDeserialize(ByteBuffer* buffer, FlightData* out) {
   buffer->Clear();
 
   // TODO(wesm): Where and when should we verify that the FlightData is not
-  // malformed or missing components?
+  // malformed?
+
+  // Set the default value for an unspecified FlightData body. The other
+  // fields can be null if they're unspecified.
+  if (out->body == nullptr) {
+    out->body = std::make_shared<Buffer>(nullptr, 0);
+  }
 
   return grpc::Status::OK;
 }