diff --git a/conan/tools/gnu/gnutoolchain.py b/conan/tools/gnu/gnutoolchain.py
index 336d8e06aff..6407f5c3027 100644
--- a/conan/tools/gnu/gnutoolchain.py
+++ b/conan/tools/gnu/gnutoolchain.py
@@ -237,7 +237,7 @@ def _filter_list_empty_fields(v):
 
     @staticmethod
     def _dict_to_list(flags):
-        return [f"{k}={v}" if v else k for k, v in flags.items()]
+        return [f"{k}={v}" if v is not None else k for k, v in flags.items()]
 
     @property
     def cxxflags(self):
diff --git a/test/unittests/tools/gnu/test_gnutoolchain.py b/test/unittests/tools/gnu/test_gnutoolchain.py
index cf053530e1f..c53f9d7bb83 100644
--- a/test/unittests/tools/gnu/test_gnutoolchain.py
+++ b/test/unittests/tools/gnu/test_gnutoolchain.py
@@ -192,5 +192,9 @@ def test_update_or_prune_any_args(cross_building_conanfile):
     assert "'--force" not in new_autoreconf_args
     # Add new value to make_args
     at.make_args.update({"--new-complex-flag": "new-value"})
+    at.make_args.update({"--new-empty-flag": ""})
+    at.make_args.update({"--new-no-value-flag": None})
     new_make_args = cmd_args_to_string(GnuToolchain._dict_to_list(at.make_args))
     assert "--new-complex-flag=new-value" in new_make_args
+    assert "--new-empty-flag=" in new_make_args
+    assert "--new-no-value-flag" in new_make_args and "--new-no-value-flag=" not in new_make_args