diff --git a/src/ert/storage/local_experiment.py b/src/ert/storage/local_experiment.py
index 4807a7774fd..5e6f877e08b 100644
--- a/src/ert/storage/local_experiment.py
+++ b/src/ert/storage/local_experiment.py
@@ -207,7 +207,7 @@ def update_parameters(self) -> List[str]:
 
     @cached_property
     def observations(self) -> Dict[str, xr.Dataset]:
-        observations = list(self.mount_point.glob("observations/*"))
+        observations = sorted(list(self.mount_point.glob("observations/*")))
         return {
             observation.name: xr.open_dataset(observation, engine="scipy")
             for observation in observations
diff --git a/tests/unit_tests/analysis/test_es_update.py b/tests/unit_tests/analysis/test_es_update.py
index 6584801ff20..5b69dfece36 100644
--- a/tests/unit_tests/analysis/test_es_update.py
+++ b/tests/unit_tests/analysis/test_es_update.py
@@ -594,3 +594,15 @@ def test_temporary_parameter_storage_with_inactive_fields(
             ensemble._path / f"realization-{iens}" / f"{param_group}.nc", engine="scipy"
         )
         np.testing.assert_array_equal(ds["values"].values[0], fields[iens]["values"])
+
+
+def test_that_observations_keep_sorting(snake_oil_case_storage, snake_oil_storage):
+    """
+    The order of the observations influence the update as it affects the
+    perturbations, so we make sure we maintain the order throughout.
+    """
+    ert_config = snake_oil_case_storage
+    prior_ens = snake_oil_storage.get_ensemble_by_name("default_0")
+    assert list(ert_config.observations.keys()) == list(
+        prior_ens.experiment.observations.keys()
+    )