In a large pot, heat the vegetable oil over medium heat.
Add the onion, bell pepper, and celery, and sauté until softened, about 5 minutes.
Stir in the garlic and cook for an additional minute.
Add the sliced andouille sausage to the pot and cook until browned, about 5 minutes.
Stir in the shrimp and crab meat, cooking for another 3 minutes until the shrimp turn pink.
Pour in the diced tomatoes, seafood stock, Worcestershire sauce, Cajun seasoning, thyme, and bay leaves.
Bring the mixture to a simmer and let it cook for 30 minutes, stirring occasionally.
Season with salt and pepper to taste.
Add the sliced okra and continue to simmer for another 10 minutes.
Remove the bay leaves before serving.
Stir in the chopped parsley and green onions just before serving.
Serve the gumbo over cooked white rice.