diff --git a/Framework/PythonInterface/plugins/algorithms/WorkflowAlgorithms/SimulatedDensityOfStates.py b/Framework/PythonInterface/plugins/algorithms/WorkflowAlgorithms/SimulatedDensityOfStates.py
index 52a8d0a013186261d258eb8645643cfc14ceba14..53a1bfc27527067b6c0bbeea67aa3091ff70b862 100644
--- a/Framework/PythonInterface/plugins/algorithms/WorkflowAlgorithms/SimulatedDensityOfStates.py
+++ b/Framework/PythonInterface/plugins/algorithms/WorkflowAlgorithms/SimulatedDensityOfStates.py
@@ -6,6 +6,7 @@ import numpy as np
 import re
 import os.path
 import math
+from collections import OrderedDict
 
 from mantid.kernel import *
 from mantid.api import *
@@ -332,7 +333,8 @@ class SimulatedDensityOfStates(PythonAlgorithm):
         @param weights          :: weight data from file
         """
         # Build a dictionary of ions that the user cares about
-        partial_ions = dict()
+        # systemtests check order so use OrderedDict
+        partial_ions = OrderedDict()
 
         calc_ion_index = self.getProperty('CalculateIonIndices').value