diff --git a/openmc/mgxs/mgxs.py b/openmc/mgxs/mgxs.py
index 68cbbbe8f..d7a17201a 100644
--- a/openmc/mgxs/mgxs.py
+++ b/openmc/mgxs/mgxs.py
@@ -4901,6 +4901,7 @@ class ScatterProbabilityMatrix(MatrixMGXS):
             name, num_polar, num_azimuthal)
 
         self._rxn_type = 'scatter'
+        self._hdf5_key = 'scatter probability matrix'
         self._estimator = 'analog'
         self._valid_estimators = ['analog']
 
diff --git a/tests/test_mgxs_library_hdf5/results_true.dat b/tests/test_mgxs_library_hdf5/results_true.dat
index 5324d666c..282ffeb89 100644
--- a/tests/test_mgxs_library_hdf5/results_true.dat
+++ b/tests/test_mgxs_library_hdf5/results_true.dat
@@ -61,11 +61,6 @@ domain=10000 type=nu-fission matrix
 [[3.14909051e-03 0.00000000e+00]
  [2.74255162e-02 0.00000000e+00]]
 domain=10000 type=scatter probability matrix
-[[9.97432606e-01 2.56739409e-03]
- [2.24215247e-03 9.97757848e-01]]
-[[7.82243018e-02 1.25560869e-03]
- [2.24310192e-03 4.10531468e-02]]
-domain=10000 type=nu-scatter probability matrix
 [[9.97432606e-01 2.56739409e-03]
  [2.24215247e-03 9.97757848e-01]]
 [[7.82243018e-02 1.25560869e-03]
@@ -259,11 +254,6 @@ domain=10001 type=nu-fission matrix
 [[0.00000000e+00 0.00000000e+00]
  [0.00000000e+00 0.00000000e+00]]
 domain=10001 type=scatter probability matrix
-[[1.00000000e+00 0.00000000e+00]
- [0.00000000e+00 1.00000000e+00]]
-[[1.08778697e-01 0.00000000e+00]
- [0.00000000e+00 1.42427173e-01]]
-domain=10001 type=nu-scatter probability matrix
 [[1.00000000e+00 0.00000000e+00]
  [0.00000000e+00 1.00000000e+00]]
 [[1.08778697e-01 0.00000000e+00]
@@ -457,11 +447,6 @@ domain=10002 type=nu-fission matrix
 [[0.00000000e+00 0.00000000e+00]
  [0.00000000e+00 0.00000000e+00]]
 domain=10002 type=scatter probability matrix
-[[9.53271028e-01 4.67289720e-02]
- [2.17817469e-04 9.99782183e-01]]
-[[3.60184962e-02 2.54736726e-03]
- [2.18820864e-04 1.35884974e-01]]
-domain=10002 type=nu-scatter probability matrix
 [[9.53271028e-01 4.67289720e-02]
  [2.17817469e-04 9.99782183e-01]]
 [[3.60184962e-02 2.54736726e-03]