The Toyota RAV4 is somewhat fuel-efficient by family-vehicle standards, but it doesn't sit at the top of the small-crossover heap and won't compete with hybrids, such as Toyota's own Prius models.
Fuel-focused upgrades that were part of the RAV4's 2013 redesign included upgrading the transmission from an aging four-speed automatic to a modern six-speed, and cleaning up the aerodynamics, with the loss of the rear-mounted spare tire being an important part.
Front-wheel-drive models manage fuel economy numbers of at 23 miles per gallon city, and 30 mpg on the highway. Upgrade to all-wheel drive and you'll lower the gas mileage to 22/29 mpg. These numbers aren't class-leading. The Mazda CX-5, for instance, achieves up to 35 mpg highway, and the most efficient versions of the Ford Escape also top the RAV4's fuel economy.