diff --git a/garak/configurable.py b/garak/configurable.py
index 7ad768a76..efb9f5668 100644
--- a/garak/configurable.py
+++ b/garak/configurable.py
@@ -88,6 +88,8 @@ def _apply_config(self, config):
                     )
                 ):
                     continue
+                if isinstance(v, dict):  # if value is an existing dictionary merge
+                    v = getattr(self, k) | v
             setattr(self, k, v)  # This will set attribute to the full dictionary value
 
     def _apply_missing_instance_defaults(self):
@@ -96,6 +98,9 @@ def _apply_missing_instance_defaults(self):
             for k, v in self.DEFAULT_PARAMS.items():
                 if not hasattr(self, k):
                     setattr(self, k, v)
+                elif isinstance(v, dict):
+                    v = v | getattr(self, k)
+                    setattr(self, k, v)
 
     def _validate_env_var(self):
         if hasattr(self, "key_env_var"):
diff --git a/tests/test_configurable.py b/tests/test_configurable.py
index 4979beb16..f727002dc 100644
--- a/tests/test_configurable.py
+++ b/tests/test_configurable.py
@@ -24,7 +24,13 @@ class mockConfigurable(Configurable):
     # Configurable is coupled to hierarchy of plugin types
     __module__ = "garak.generators.mock"
 
-    DEFAULT_PARAMS = {"class_var": "from_class"}
+    DEFAULT_PARAMS = {
+        "class_var": "from_class",
+        "class_dict_var": {
+            "dict_a": "dict_val",
+            "dict_b": "dict_val",
+        },
+    }
 
     def __init__(
         self,
@@ -63,6 +69,17 @@ def test_param_provided(generator_sub_config):
 def test_class_vars_propagate_to_instance(generator_sub_config):
     m = mockConfigurable(config_root=generator_sub_config)
     assert m.class_var == m.DEFAULT_PARAMS["class_var"]
+    assert m.class_dict_var == m.DEFAULT_PARAMS["class_dict_var"]
+
+
+# when a default parameter is provided and not config_root set on the resulting object
+def test_class_dict_merge_to_instance(generator_sub_config):
+    config_dict_var = {"dict_a": "test_val", "dict_c": "test_val"}
+    generator_sub_config.generators["mock"]["class_dict_var"] = config_dict_var
+    m = mockConfigurable(config_root=generator_sub_config)
+    assert m.class_dict_var == m.DEFAULT_PARAMS["class_dict_var"] | config_dict_var
+    assert m.class_dict_var["dict_a"] == config_dict_var["dict_a"]
+    assert m.class_dict_var["dict_c"] == config_dict_var["dict_c"]
 
 
 # when a default parameter is provided and not config_root set on the resulting object