A phase-out of fossil fuel vehicles are proposed bans or discouragement (for example via taxes) on the sale of new fossil-fuel powered vehicles or use of existing fossil-fuel powered vehicles, as well the encouragement of using other forms of transportation. Vehicles that are powered by fossil fuels, such as gasoline (petrol), diesel, kerosene, and fuel oil are set to be phased out by a number of countries. It is one of the three most important parts of the general fossil fuel phase-out process, the others being the phase-out of fossil fuel power plants for electricity generation and decarbonisation of industry.

Many countries and cities around the world have stated they will ban the sale of passenger vehicles (primarily cars and buses) powered by fossil fuels such as petrol, liquefied petroleum gas, and diesel at some time in the future. Synonyms for the bans include phrases like "banning gas cars", "banning petrol cars", "the petrol and diesel car ban", or simply "the diesel ban". Another method of phase-out is the use of zero-emission zones in cities.

Reasons for banning the further sale of fossil fuel vehicles include: reducing health risks from pollution particulates, notably diesel PM10s, and other emissions, notably nitrogen oxides; meeting national greenhouse gas, such as CO₂, targets under international agreements such as the Kyoto Protocol and the Paris Agreement; or energy independence. The intent to ban vehicles powered by fossil fuels is attractive to governments as it offers a simpler compliance target, compared with a carbon tax or phase-out of fossil fuels.

The automotive industry is working to introduce electric vehicles to adapt to bans with varying success and it is seen by some in the industry as a possible source of money in a declining market. A 2020 study from the Eindhoven University of Technology showed that the manufacturing emissions of batteries of new electric cars are much smaller than what was assumed in the 2017 IVL study (around 75 kg CO₂/kWh) and that the lifespan of lithium batteries is also much longer than previously thought (at least 12 years with a mileage of 15,000 km annually): they are cleaner than internal combustion cars powered by diesel or petrol.

There is some opposition to simply moving from fossil-fuel-powered cars to electric cars, as they would still require a large proportion of urban land. On the other hand, there are many types of (electric) vehicles that take up little space, such as (cargo) bicycles and electric motorcycles and scooters. Making cycling and walking over short distances, especially in urban areas, more attractive and feasible with measures such as removing roads and parking spaces and improving cycling infrastructure and footpaths (including pavements), provides a partial alternative to replacing all fossil-fuelled vehicles with electric vehicles. Although there are as yet very few completely carfree cities (such as Venice), several are banning all cars in parts of the city, such as city centers.

The banning of fossil-fuelled vehicles of a defined scope requires authorities to enact legislation that restricts them in a certain way. Proposed methods include:

Fuel cell (electric) vehicles (FCVs or FCEVs) also allow running on (some) non-fossil fuels (i.e., hydrogen, ethanol, methanol, ).

Cities generally use the introduction of low-emission zones (LEZs) or zero-emission zones (ZEZs), sometimes with an accompanying air quality certificate sticker such as Crit'air (France), to restrict the use of fossil-fuelled cars in some or all of its territory. These zones are growing in number, size, and strictness. Some city bans in countries such as Italy, Germany, and Switzerland are only temporarily activated during particular times of the day, during winter, or when there is a smog alert (for example, in Italy in January 2020); these do not directly contribute to the phase-out of fossil fuel vehicles, but they make owning and using such vehicles less attractive as their utility is restricted and the cost of driving them increases.