diff --git a/moto/ssm/models.py b/moto/ssm/models.py
index d88deb808..1ffc1a9d5 100644
--- a/moto/ssm/models.py
+++ b/moto/ssm/models.py
@@ -2062,7 +2062,11 @@ class SimpleSystemManagerBackend(BaseBackend):
                     "formed as a mix of letters, numbers and the following 3 symbols .-_"
                 )
             raise ValidationException(invalid_prefix_error)
-        if not parameter_type and not overwrite and not self._parameters[name]:
+        if (
+            not parameter_type
+            and not overwrite
+            and not (name in self._parameters and self._parameters[name])
+        ):
             raise ValidationException(
                 "A parameter type is required when you create a parameter."
             )
diff --git a/tests/test_ssm/test_ssm_boto3.py b/tests/test_ssm/test_ssm_boto3.py
index 29aa73ade..9a97573bf 100644
--- a/tests/test_ssm/test_ssm_boto3.py
+++ b/tests/test_ssm/test_ssm_boto3.py
@@ -448,6 +448,9 @@ def test_put_parameter_no_type():
         == "A parameter type is required when you create a parameter."
     )
 
+    # Ensure backend state is consistent
+    assert client.describe_parameters()
+
 
 @mock_ssm
 def test_update_parameter():