2020 GMC Sierra
26MPG
Combined
17
Trims
2020
2021 →
Updated February 27, 2026
Get the full picture on the 2020 GMC Sierra. As a Truck, it achieves 16–26 combined MPG depending on trim and has not yet been rated by NHTSA. Below you’ll find detailed specs for every trim, plus recall information and competitor comparisons.
2020 GMC Sierra Specifications
| Spec | Value |
|---|---|
| Combined MPG | 16–26 combined MPG depending on trim |
| City MPG | 23 |
| Highway MPG | 30 |
| Body Style | Truck |
| Fuel Type | Regular |
| Drive | RWD |
| Available Trims | 17 |
Available Trims
| Trim | MPG (City/Hwy/Combined) | Engine | Transmission |
|---|---|---|---|
| Auto | 16/21/17 | 4.3L 6cyl | Automatic 6-spd |
| Auto | 17/23/19 | 5.3L 8cyl | Automatic 8-spd |
| Auto | 19/22/20 | 2.7L 4cyl | Automatic 8-spd |
| Auto | 23/30/26 | 3.0L 6cyl | Automatic 10-spd |
| Auto | 15/21/17 | 5.3L 8cyl | Automatic 6-spd |
| Auto | 15/19/16 | 5.3L 8cyl | Automatic 6-spd |
| Sport | 20/23/21 | 2.7L 4cyl | Automatic 8-spd |
| Auto | 17/24/20 | 5.3L 8cyl | Automatic 8-spd |
| Auto | 16/22/18 | 5.3L 8cyl | Automatic 8-spd |
| Auto | 16/22/19 | 5.3L 8cyl | Automatic 10-spd |
| Sport | 19/22/20 | 2.7L 4cyl | Automatic 8-spd |
| Auto | 15/20/17 | 6.2L 8cyl | Automatic 10-spd |
| Auto | 15/20/17 | 5.3L 8cyl | Automatic 6-spd |
| Auto | 22/26/24 | 3.0L 6cyl | Automatic 10-spd |
| Auto | 19/22/20 | 2.7L 4cyl | Automatic 8-spd |
| Auto | 15/20/17 | 4.3L 6cyl | Automatic 6-spd |
| Auto | 14/19/16 | 5.3L 8cyl | Automatic 6-spd |
Annual Fuel Cost
Based on EPA estimates, the 2020 GMC Sierra costs approximately $2,452 per year in fuel. This assumes 15,000 miles driven annually and current fuel prices.
Compare the 2020 GMC Sierra
See how it stacks up against similar vehicles:
Other Model Years
- 2026 GMC Sierra
- 2025 GMC Sierra
- 2024 GMC Sierra
- 2023 GMC Sierra
- 2022 GMC Sierra
- 2021 GMC Sierra
- 2020 (this page)
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