Heat the oven to 375°F. Line a rimmed baking sheet with parchment paper.
Cook the orzo according to the package directions. Drain it well and set it aside to cool slightly.
Warm the olive oil in a skillet over medium heat. Add the spinach and cook, stirring, until wilted. Let it cool, then gently squeeze out excess moisture.
In a large bowl, combine the ground turkey, egg, breadcrumbs, feta, red onion, oregano, garlic powder, salt, pepper, and lemon juice. Add the cooked orzo and spinach.
Mix gently until the ingredients are evenly combined. Shape the mixture into a compact loaf on the prepared baking sheet.
Bake until the center reaches 165°F on an instant-read thermometer, about 45 to 55 minutes. Rest the loaf for 10 minutes before slicing.