Preheat an outdoor grill for medium heat and lightly oil the grate.
Meanwhile, whisk mayonnaise, lemon juice, and seafood seasoning together in a bowl until smooth. Set aside.
Cook corn on the preheated grill for 12 minutes, flipping every 3 minutes until all sides are starting to brown. Spread mayonnaise mixture all over corn; top with Parmesan cheese and parsley.
Grilled Old Bay Corn on the Cob · Dinner Match Lab | Dinner Match Lab