Heat the oil in fry pan over medium heat.
Add shrimp and cook until pink both sides about (3-4 minutes/side)
Remove from fry pan and set aside.
Add sliced bell peppers, broccoli and mushrooms to pan and sauté for about 3-4 minutes, until they are slightly softened.
Add the minced garlic to the pan and sauté for another minute, until fragrant.
Return the cooked shrimp to the fry pan and add soy sauce and oyster sauce.
Stir everything together and cook for an additional minute or so, until everything is heated through and the sauce is evenly distributed.
Season with salt and pepper to taste, garnish with green onion.