diff --git a/compose/config/config.py b/compose/config/config.py
index c11460fa5..7e77421e5 100644
--- a/compose/config/config.py
+++ b/compose/config/config.py
@@ -818,6 +818,7 @@ def merge_service_dicts(base, override, version):
     md.merge_mapping('ulimits', parse_ulimits)
     md.merge_mapping('networks', parse_networks)
     md.merge_mapping('sysctls', parse_sysctls)
+    md.merge_mapping('depends_on', parse_depends_on)
     md.merge_sequence('links', ServiceLink.parse)
 
     for field in ['volumes', 'devices']:
@@ -825,7 +826,7 @@ def merge_service_dicts(base, override, version):
 
     for field in [
         'ports', 'cap_add', 'cap_drop', 'expose', 'external_links',
-        'security_opt', 'volumes_from', 'depends_on',
+        'security_opt', 'volumes_from',
     ]:
         md.merge_field(field, merge_unique_items_lists, default=[])
 
@@ -920,6 +921,9 @@ parse_environment = functools.partial(parse_dict_or_list, split_env, 'environmen
 parse_labels = functools.partial(parse_dict_or_list, split_kv, 'labels')
 parse_networks = functools.partial(parse_dict_or_list, lambda k: (k, None), 'networks')
 parse_sysctls = functools.partial(parse_dict_or_list, split_kv, 'sysctls')
+parse_depends_on = functools.partial(
+    parse_dict_or_list, lambda k: (k, {'condition': 'service_started'}), 'depends_on'
+)
 
 
 def parse_ulimits(ulimits):
diff --git a/tests/unit/config/config_test.py b/tests/unit/config/config_test.py
index ca7c61683..ab8bfcfcc 100644
--- a/tests/unit/config/config_test.py
+++ b/tests/unit/config/config_test.py
@@ -1713,6 +1713,40 @@ class ConfigTest(unittest.TestCase):
             }
         }
 
+    def test_merge_depends_on_no_override(self):
+        base = {
+            'image': 'busybox',
+            'depends_on': {
+                'app1': {'condition': 'service_started'},
+                'app2': {'condition': 'service_healthy'}
+            }
+        }
+        override = {}
+        actual = config.merge_service_dicts(base, override, V2_1)
+        assert actual == base
+
+    def test_merge_depends_on_mixed_syntax(self):
+        base = {
+            'image': 'busybox',
+            'depends_on': {
+                'app1': {'condition': 'service_started'},
+                'app2': {'condition': 'service_healthy'}
+            }
+        }
+        override = {
+            'depends_on': ['app3']
+        }
+
+        actual = config.merge_service_dicts(base, override, V2_1)
+        assert actual == {
+            'image': 'busybox',
+            'depends_on': {
+                'app1': {'condition': 'service_started'},
+                'app2': {'condition': 'service_healthy'},
+                'app3': {'condition': 'service_started'}
+            }
+        }
+
     def test_external_volume_config(self):
         config_details = build_config_details({
             'version': '2',