diff --git a/lib/gpgme/data.rb b/lib/gpgme/data.rb
index dbcb0b5..a6d4efe 100644
--- a/lib/gpgme/data.rb
+++ b/lib/gpgme/data.rb
@@ -45,6 +45,8 @@ def new(object = nil)
           object
         elsif object.is_a?(Integer)
           from_fd(object)
+        elsif defined?(StringIO) and object.is_a?(StringIO)
+          from_io(object)
         elsif object.respond_to? :to_str
           from_str(object.to_str)
         elsif object.respond_to? :to_io