US tanks in Vietnam generally had a role in providing infantry fire support. Tank vs tank engagements did occur in Vietnam, but were not common early on. One example that sticks out was an engagement at Ben Het Special forces camp in May 1969, where a small engagement occurred between US M48 tanks and NVA PT-76 light tanks, resulting in the loss of 1 M48 and two NVA PT-76 light tanks. Armored clashes between ARVN and NVA tanks would become more common with the NVA offensive into South Vietnam, but NVA tanks losses were often heavy due to the decisive input of US air power: The BGM-71 TOW missile system saw its combat debut at An Loc in 1972, when TOW missiles launched by Huey helicopters efficiently destroyed significant numbers of NVA tanks.

The rugged terrain of Vietnam could be highly restrictive in deploying armour, which meant that heavier US tanks such as the M48 could sometimes find themselves restricted to roads. This meant that the M48 often found itself in the role of ambush breaking and convoy protection, a role it was assisted in thanks to the availability of canister and flechette rounds for its main gun. These projectiles turned the 90mm cannon into an enormous shotgun shell (firing either steel pellets or small darts) and were devastating against both exposed enemies and vegetation, and were noted for their ability to expose enemy firing positions by stripping away greenery and cover to allow them to be neutralized and destroyed. The suppressive and psychological effects of such rounds was also highly intimidating: flechette rounds in particular were enthusiastically nicknamed Beehives, for the humming moan the cloud of darts made, even though their actual effectiveness against targets in thick vegetation was relatively limited.

As well as this, US tanks found themselves providing fire support to static positions such as landing zones and firebases, and, in places where the terrain could support them, in sweep and clear operations in conjunction with M113 carriers in thick brush, where armoured vehicles would drive their way through the vegetation in order to drive out NVA and Viet Cong fighters. North Vietnamese accounts mention how intimidating it was for large armoured vehicles to crush their way through jungle, and were particular impressed by the M113 is this regard due to its impressive mobility and firepower when carrying out these operations.

US forces tried to meet the mobility issues that limited heavy tank deployment by using light tanks. The aluminium armoured M551 Sheridan was a notable example that achieved a mixed combat record in Vietnam; some praised it for its superlative mobility in the Viet countryside thanks to its lightweight construction, and enjoyed the firepower its 152mm gun provided, but others criticized it for its inherent vulnerability to enemy fire and landmines (and its penchant for burning and melting when hit), the poor rate of fire its main gun provided during "mad minute" anti-ambush drills, and its limited ability at crushing vegetation in "jungle busting" missions. A similar vehicle in this regard was the US Marine operated M50 Ontos, a lightweight tank destroyer consisting of 6 105mm recoilless rifles mounted on lightly armoured tracked platform. Although poorly protected and appearing to be inherently jury-rigged, the Ontos was much loved by troops for the devastatingly accurate and effective fire support it provided against everything from snipers to bunkers, and combat accounts talk of North Vietnamese resistance abruptly tailing off when the distinctive form of the Ontos loped into view.