According to the search results, the most fuel-efficient SUVs for 2023 are:

• 2023 Nissan Kicks: The most fuel-efficient non-hybrid SUV, with an EPA-estimated 31 mpg in the city and 36 mpg on the highway.
• 2023 Hyundai Venue: A subcompact SUV with a combined gas mileage rating of 31 mpg.
• 2023 Toyota RAV4 Hybrid: A compact SUV with an EPA-estimated 40 mpg combined.
• 2023 Honda CR-V Hybrid: A compact SUV with an EPA-estimated 38 mpg combined.
• 2023 Kia Sportage Hybrid: A compact SUV with an EPA-estimated 42 mpg in the city and 44 mpg on the highway.
• 2023 Toyota Highlander Hybrid: A midsize SUV with an EPA-estimated 36 mpg combined.

Its worth noting that the fuel efficiency of an SUV can vary depending on the specific model and configuration.