diff --git a/pyhocon/config_parser.py b/pyhocon/config_parser.py
index 6846589d..2ac789c6 100644
--- a/pyhocon/config_parser.py
+++ b/pyhocon/config_parser.py
@@ -535,7 +535,10 @@ def _resolve_variable(cls, config, substitution):
         """
         variable = substitution.variable
         try:
-            return True, config.get(variable)
+            if substitution.self_ref:
+                return True, substitution.parent.overriden_value
+            else:
+                return True, config.get(variable)
         except ConfigMissingException:
             # default to environment variable
             value = os.environ.get(variable)
@@ -859,10 +862,10 @@ def postParse(self, instring, loc, token_list):
                 else:
                     value = values[0]
                     if isinstance(value, list) and operator == "+=":
-                        value = ConfigValues([ConfigSubstitution(key, True, '', False, loc), value], False, loc)
+                        value = ConfigValues([ConfigSubstitution(key, True, '', False, loc, self_ref=True), value], False, loc)
                         config_tree.put(key, value, False)
                     elif isinstance(value, unicode) and operator == "+=":
-                        value = ConfigValues([ConfigSubstitution(key, True, '', True, loc), ' ' + value], True, loc)
+                        value = ConfigValues([ConfigSubstitution(key, True, '', True, loc, self_ref=True), ' ' + value], True, loc)
                         config_tree.put(key, value, False)
                     elif isinstance(value, list):
                         config_tree.put(key, value, False)
diff --git a/pyhocon/config_tree.py b/pyhocon/config_tree.py
index 9996df53..dab47968 100644
--- a/pyhocon/config_tree.py
+++ b/pyhocon/config_tree.py
@@ -602,7 +602,7 @@ def __repr__(self):  # pragma: no cover
 
 
 class ConfigSubstitution(object):
-    def __init__(self, variable, optional, ws, instring, loc):
+    def __init__(self, variable, optional, ws, instring, loc, self_ref=False):
         self.variable = variable
         self.optional = optional
         self.ws = ws
@@ -610,6 +610,7 @@ def __init__(self, variable, optional, ws, instring, loc):
         self.parent = None
         self.instring = instring
         self.loc = loc
+        self.self_ref = self_ref
 
     def raw_str(self):
         return self.variable
diff --git a/tests/test_config_parser.py b/tests/test_config_parser.py
index 13a130fc..1c0942a8 100644
--- a/tests/test_config_parser.py
+++ b/tests/test_config_parser.py
@@ -807,7 +807,7 @@ def test_self_ref_substitution_array(self):
         )
         assert config.get("x") == [-3, -2, -1, 0, 1, 2, 3, 4, 5, 6]
 
-    def test_self_append_array(self):
+    def test_self_extend_array(self):
         config = ConfigFactory.parse_string(
             """
             x = [1,2]
@@ -816,6 +816,37 @@ def test_self_append_array(self):
         )
         assert config.get("x") == [1, 2, 3, 4]
 
+    def test_self_append_array(self):
+        config = ConfigFactory.parse_string(
+            """
+            x = [1,2]
+            x += 3
+            """
+        )
+        assert config.get("x") == [1, 2, 3]
+
+    def test_self_extend_array_inside_dict(self):
+        config = ConfigFactory.parse_string(
+            """
+            d {
+                x = [1,2]
+                x += [3,4]
+            }
+            """
+        )
+        assert config.get("d.x") == [1, 2, 3, 4]
+
+    def test_self_append_array_inside_dict(self):
+        config = ConfigFactory.parse_string(
+            """
+            d {
+                x = [1,2]
+                x += 3
+            }
+            """
+        )
+        assert config.get("d.x") == [1, 2, 3]
+
     def test_self_append_string(self):
         '''
         Should be equivalent to
@@ -830,6 +861,22 @@ def test_self_append_string(self):
         )
         assert config.get("x") == "abc def"
 
+    def test_self_append_string_inside_dict(self):
+        '''
+        Should be equivalent to
+        x = abc
+        x = ${?x} def
+        '''
+        config = ConfigFactory.parse_string(
+            """
+            d {
+                x = abc
+                x += def
+            }
+            """
+        )
+        assert config.get("d.x") == "abc def"
+
     def test_self_append_non_existent_string(self):
         '''
         Should be equivalent to x = ${?x} def
@@ -841,7 +888,7 @@ def test_self_append_non_existent_string(self):
         )
         assert config.get("x") == " def"
 
-    def test_self_append_nonexistent_array(self):
+    def test_self_extend_nonexistent_array(self):
         config = ConfigFactory.parse_string(
             """
             x += [1,2]
@@ -849,6 +896,14 @@ def test_self_append_nonexistent_array(self):
         )
         assert config.get("x") == [1, 2]
 
+    def test_self_append_nonexistent_array(self):
+        config = ConfigFactory.parse_string(
+            """
+            x += 1
+            """
+        )
+        assert config.get("x") == [1]
+
     def test_self_append_object(self):
         config = ConfigFactory.parse_string(
             """
@@ -858,6 +913,17 @@ def test_self_append_object(self):
         )
         assert config.get("x") == {'a': 1, 'b': 2}
 
+    def test_self_append_object_inside_dict(self):
+        config = ConfigFactory.parse_string(
+            """
+            d {
+                x = {a: 1}
+                x += {b: 2}
+            }
+            """
+        )
+        assert config.get("d.x") == {'a': 1, 'b': 2}
+
     def test_self_append_nonexistent_object(self):
         config = ConfigFactory.parse_string(
             """