Extra virgin olive oil is the most commonly used oil for vinaigrette dressings however you can use other oils like avocado oil, grape seed oil, or canola oil based on your preference. The most important tip I have for selecting an oil for vinaigrette is: taste the oil and make sure you like the flavor. If it's bitter, your vinaigrette will be bitter. If it's fruity, that fruitiness will shine through.