diff --git a/src/ert/config/analysis_config.py b/src/ert/config/analysis_config.py
index 6bb55eddf1d..51fc80cef7c 100644
--- a/src/ert/config/analysis_config.py
+++ b/src/ert/config/analysis_config.py
@@ -126,7 +126,14 @@ def __init__(
 
                 var_name = "inversion"
             key = var_name.lower()
-            options[module_name][key] = value
+            try:
+                options[module_name][key] = value
+            except KeyError:
+                all_errors.append(
+                    ConfigValidationError(
+                        f"Invalid configuration: ANALYSIS_SET_VAR {module_name} {var_name}"
+                    )
+                )
 
         if errors:
             all_errors.append(
diff --git a/tests/unit_tests/config/test_analysis_config.py b/tests/unit_tests/config/test_analysis_config.py
index 0f58853ef98..7bf48d8dcdf 100644
--- a/tests/unit_tests/config/test_analysis_config.py
+++ b/tests/unit_tests/config/test_analysis_config.py
@@ -345,6 +345,10 @@ def test_misfit_configuration(config, expected):
             [["OBSERVATIONS", "SAUTO_SCALE", "OBS_*"]],
             pytest.raises(ConfigValidationError, match="Unknown variable"),
         ),
+        (
+            [["NOT_A_THING", "AUTO_SCALE", "OBS_*"]],
+            pytest.raises(ConfigValidationError, match="ANALYSIS_SET_VAR NOT_A_THING"),
+        ),
     ],
 )
 def test_config_wrong_module(config, expectation):