Summary

• With 1,676 currently listed for sale and an average price of $51,088.00, 30.7% of 2021 GMC Sierras 2500HD for sale on CarGurus are rated as good or great deals.

• Favorably reviewed: Owners rated the 2021 GMC Sierra 2500HD 5 / 5 stars.

• 79.0% of 2021 Sierra 2500HD models on CarGurus are accident free.

Why it stands out

The 2021 GMC Sierra 2500HD stands out as a heavy-duty pickup that leans more upscale than many rivals. In this generation, GMC offers more trim levels than the related Chevy Silverado 2500HD, along with a broader range of upscale options and features. The Denali and Denali Ultimate trims are described as more luxurious than the Silverado version’s top-tier High Country trim, which helps give the Sierra 2500HD a more premium feel than many trucks in its class.

For 2021, the Sierra 2500HD comes with a 6.6-liter V8 gas engine paired with a six-speed automatic transmission, and it is also available with a 6.6-liter Duramax turbodiesel V8 engine and a 10-speed automatic transmission from Allison. Rear- and four-wheel drive are available. Buyers can choose from Pro, SLE, SLT, AT4, AT4X, Denali, and Denali Ultimate trims, with the AT4 models adding off-road hardware and accessories such as skid plates, off-road suspension upgrades, and a more robust transfer case. The Denali trims add luxury cabin features, while available configurations include Regular Cab, Crew Cab, and Double Cab body styles with 7-foot or 8-foot-2-inch cargo beds.

The truck’s appeal also comes from its equipment list. The generation includes Bluetooth, Android Auto, Apple CarPlay, and wifi hotspot accessibility with the GMC infotainment system, plus available features such as remote keyless entry and rear-seat reminders. More upscale models can add a Bose Premium audio system, power-adjustable front seats, chrome grille trim, dual-zone automatic climate control, and power-folding tailgate options. At the same time, shoppers should be aware that this generation has a number of reported problems, including check engine lights tied to diesel particulate filters or emissions sensors, sluggish infotainment responses, rough or delayed shifts, electrical glitches, MultiPro tailgate issues, and faulty trailer brake controllers.

Other model years to consider

• 2025 GMC Sierra 2500HD

  • Average price: $74,368.00
  • Good/great deal percentage: 33.7%
  • User rating: 5 / 5
  • Total listings: 4,162

• 2024 GMC Sierra 2500HD

  • Average price: $67,942.00
  • Good/great deal percentage: 33.3%
  • User rating: 4.2 / 5
  • Total listings: 4,162

• 2020 GMC Sierra 2500HD

  • Average price: $49,670.00
  • Good/great deal percentage: 29.7%
  • User rating: 4.86 / 5
  • Total listings: 1,127

This analysis is based on CarGurus' proprietary market data from August 10, 2026, CarGurus experts' opinions, and generative AI.