Preheat your oven to 375°F. Line a large baking sheet with parchment paper. Cut your loaf into 3/4-inch cubes and place them in a large bowl.
Drizzle olive oil over the bread cubes. Sprinkle with Italian seasoning, garlic powder, salt, and black pepper. Toss gently to coat evenly.
Spread the seasoned bread cubes in a single layer on the prepared baking sheet. Bake for 15 to 20 minutes, tossing once halfway through, until the croutons are golden and crisp.
Remove the baking sheet from the oven and let the croutons cool completely. Enjoy immediately or store in an airtight container for up to 1 week.