2026 GMC Yukon full-size SUV — covering its main engine options (gas V8s and the diesel): 

🚙 2026 GMC Yukon — EPA City / Highway MPG

🛻 3.0 L Duramax Turbo-Diesel (most efficient)

• City: ~ 21 MPG

• Highway: ~ 26 MPG (RWD)

• With 4WD it’s slightly lower (about 20 / 24 MPG). 

🛻 5.3 L V8 Gas

• City: ~ 15 MPG

• Highway: ~ 20 MPG (RWD)

• With 4WD: ~ 15 / 19 MPG. 

🛻 6.2 L V8 Gas (higher-output option)

• City: ~ 14–15 MPG

• Highway: ~ 18–20 MPG (RWD/4WD). 

📊 Quick MPG Summary

👉 The diesel engine clearly offers the best city and highway fuel economy of the available powertrains; the gas-powered V8s are typical for a large SUV of this size but understandably lower overall. 

Let me know if you’d like estimated driving range per tank (based on Yukon’s fuel tank size and these mpg figures) or a comparison with the GMC Yukon XL!