There's just one drivetrain offered with the Toyota Avalon, so it shouldn't come as a surprise that the EPA rates it just one way, too.
The Avalon earns an EPA rating of 19/28 mpg, a figure that Toyota says will best the gas-only version of the Buick LaCrosse. Of course, Buick now fields an eAssist LaCrosse with up to 32 mpg on the highway, while the new Hyundai Azera boasts a highway rating of 29 mpg, just a mile per gallon better than the Avalon.
Relative to most other vehicles that can also fit five or six occupants with the same level of comfort—namely, large crossover vehicles like the Buick Enclave or Ford Flex—that makes the Avalon a very green machine.
Toyota's promised that all of its vehicles would have a hybrid option by 2020, but as of yet, there are no plans to fit the current Avalon with Toyota's Hybrid Synergy Drive, despite the fact the Avalon shares its architecture and its assembly plant with the Camry Hybrid.