Heat the olive oil in a large pot over medium heat. Add the diced onion and cook until it softens, about 5 minutes.
Stir in the minced garlic and cook for 1 minute until fragrant.
Add the rinsed lentils, dried oregano, bay leaves, and vegetable broth to the pot. Bring the mixture to a boil.
Reduce the heat to low, cover the pot, and simmer for 25 to 30 minutes until the lentils are tender.
Remove the bay leaves. Stir in the lemon juice, then season with salt and black pepper to taste. Serve warm.