Preheat oven to 425 F and line a rimmed baking sheet with silicone baking mat.
Place the cubed sweet potatoes and sliced red onion on the prepared baking sheet. Drizzle the olive oil over the sweet potatoes and red onion and gently toss. Add the sliced sausage in with the sweet potatoes and red onion on the baking sheet.
Roast in the preheated oven for 30 to 35 minutes. Meanwhile, peel and slice the apples. Add to the sheet pan with everything else and cook for another 10 minutes. Let cool slightly before serving.
Serve Sheet Pan Sausage with Sweet Potatoes and Apples, as is or with side salad or favorite veggies. Enjoy!