A: The most fuel-efficient Buick Regal Sportback is the 2019 Buick Regal Sportback GS which gets 19 MPG City and 27 MPG Highway.

It is important to remember factors such as driving style, weather conditions, and the use of features such as Eco mode can impact fuel efficiency. Fuel economy figures are based on EPA estimates for when vehicle sold as new. Fuel economy may vary for reasons like driving conditions and vehicle history. Unless specified, figures are for vehicles equipped with an automatic transmission. See fueleconomy.gov.