diff --git a/lib/galaxy/tools/evaluation.py b/lib/galaxy/tools/evaluation.py
index 0bad804b678..4f4b5afded4 100644
--- a/lib/galaxy/tools/evaluation.py
+++ b/lib/galaxy/tools/evaluation.py
@@ -35,6 +35,7 @@ from galaxy.tools.wrappers import (
 )
 from galaxy.util import (
     find_instance_nested,
+    listify,
     unicodify,
 )
 from galaxy.util.bunch import Bunch
@@ -254,6 +255,8 @@ class ToolEvaluator(object):
                 )
                 input_values[input.name] = wrapper
             elif isinstance(input, SelectToolParameter):
+                if input.multiple:
+                    value = listify(value)
                 input_values[input.name] = SelectToolParameterWrapper(
                     input, value, other_values=param_dict, path_rewriter=self.unstructured_path_rewriter)
             else:
diff --git a/lib/galaxy/util/__init__.py b/lib/galaxy/util/__init__.py
index 9961a518cc1..3ed0f8cf423 100644
--- a/lib/galaxy/util/__init__.py
+++ b/lib/galaxy/util/__init__.py
@@ -974,7 +974,9 @@ def listify(item, do_strip=False):
     """
     if not item:
         return []
-    elif isinstance(item, list) or isinstance(item, tuple):
+    elif isinstance(item, list):
+        return item
+    elif isinstance(item, tuple):
         return list(item)
     elif isinstance(item, string_types) and item.count(','):
         if do_strip: