diff --git a/cylc/flow/option_parsers.py b/cylc/flow/option_parsers.py
index e9145010b75..19705672209 100644
--- a/cylc/flow/option_parsers.py
+++ b/cylc/flow/option_parsers.py
@@ -831,6 +831,9 @@ def cleanup_sysargv(
                     not in ['store_true', 'store_false']
                 ):
                     sys.argv.pop(index)
+            elif arg in [i.split('=')[0] for i in sys.argv]:
+                index = [i.split('=')[0] for i in sys.argv].index(arg)
+                sys.argv.pop(index)
 
     # replace compound script name:
     sys.argv[1] = script_name
diff --git a/tests/unit/test_option_parsers.py b/tests/unit/test_option_parsers.py
index 332851d34c4..e3831a1daea 100644
--- a/tests/unit/test_option_parsers.py
+++ b/tests/unit/test_option_parsers.py
@@ -397,6 +397,19 @@ def test_combine_options(inputs, expect):
             'play --foo something myworkflow'.split(),
             id='no path given'
         ),
+        param(
+            'vip --bar=something'.split(),
+            {
+                'script_name': 'play',
+                'workflow_id': 'myworkflow',
+                'compound_script_opts': [
+                    OptionSettings(['--bar', '-b'])],
+                'script_opts': [],
+                'source': './myworkflow',
+            },
+            'play myworkflow'.split(),
+            id='removes --key=value'
+        ),
     ]
 )
 def test_cleanup_sysargv(monkeypatch, argv_before, kwargs, expect):