Place the cherry tomatoes, zucchini, and bell pepper on a baking sheet. Drizzle with olive oil, and sprinkle with salt and black pepper. Toss to coat.
Roast the vegetables in the preheated oven for 20-25 minutes, until tender and slightly charred.
While the vegetables are roasting, bring the water to a boil in a saucepan. Add the quinoa, reduce heat to low, cover, and simmer for 15 minutes, or until the water is absorbed and the quinoa is tender.
Fluff the quinoa with a fork and transfer to a large mixing bowl. Add the roasted vegetables and toss to combine.