Drizzle the olive oil into a large saute pan and bring to medium heat. Add the onion and stir to coat. Cook for 1-2 minutes until softened.

Add the remaining vegetables (carrots, zucchini, yellow squash, green beans, corn, and bell pepper) as well as the salt and pepper and stir to combine. Cover the pan and reduce the heat to medium-low. Cook, removing the lid briefly to stir halfway through, for 5 minutes, covered.

Remove the lid and turn the heat back up to medium. Add the garlic and stir to combine. Cook, stirring occasionally, for another 3-5 minutes until the vegetables are just tender.