According to Honda spec sheets, fuel tank capacity is . gallons. Some say they can get more in, but the most I’ve ever put in was . so I must have been running on fumes. RTL, ROTY billet cubby cover, door sills and license plate frame..Find detailed specifications and information for your Honda Ridgeline. Vehicle Info PARTS SERVICE Dealers My Account You searched for Fuel Tank Capacity . gal Required Fuel Regular Unleaded Based on EPA mileage ratings. Use for comparison purposes only..