In a medium bowl, mix together olive oil, maple syrup, soy sauce, garlic, vinegar and pepper. Pour into a large resealable baggie; add veggies and turn several times to coat. Refrigerate at least 4 hours or overnight.
When ready to roast veggies, preheat oven to 425 degrees.
Place veggies on skewers leaving at least ½” between them so they cook evenly. Discard remaining marinade.
Place kabobs on a baking sheet; roast for 25 minutes, flipping once during cooking.