diff --git a/openmc/summary.py b/openmc/summary.py
index 41bae7f26b..43224334d0 100644
--- a/openmc/summary.py
+++ b/openmc/summary.py
@@ -14,6 +14,11 @@ _VERSION_SUMMARY = 6
 class Summary:
     """Summary of model used in a simulation.
 
+    Parameters
+    ----------
+    filename : str or path-like
+        Path to file to load
+
     Attributes
     ----------
     date_and_time : str
@@ -33,8 +38,9 @@ class Summary:
     """
 
     def __init__(self, filename):
+        filename = str(filename)
         if not filename.endswith(('.h5', '.hdf5')):
-            msg = 'Unable to open "{0}" which is not an HDF5 summary file'
+            msg = f'Unable to open "{filename}" which is not an HDF5 summary file'
             raise ValueError(msg)
 
         self._f = h5py.File(filename, 'r')