TEV may refer to:

• Transient Earth Voltage: a term for voltages appearing on the metal work of switchgear due to internal partial discharges
• TeV, or teraelectronvolt, a measure of energy
• Total Enterprise Value, a financial measure
• Total Economic Value, an economic measure
• Tracked Electric Vehicles, an open source electric vehicle system proposed by the TEV Project
• Tobacco etch virus, a plant pathogenic virus of the family Potyviridae
  • Tobacco etch virus protease, an enzyme commonly used in biochemistry
• Today's English Version, a former name for the Good News Bible
• TEV, a ship prefix for Turbo-electric Vessel, usually with steam driven turbines.
• Thermal expansion valve, a refrigeration system component

In physics, the electronvolt (symbol eV; also written electron volt) is a unit of energy equal to approximately 160 zeptojoules (symbol zJ) or  joules (symbol J). By definition, it is the amount of energy gained (or lost) by the charge of a single electron moved across an electric potential difference of one volt. Thus it is 1 volt (1 joule per coulomb, ) multiplied by the elementary charge (e, or [1]{physconst|e}}). Therefore, one electron volt is equal to Historically, the electron volt was devised as a standard unit of measure through its usefulness in electrostatic particle accelerator sciences because a particle with charge q has an energy after passing through the potential V; if q is quoted in integer units of the elementary charge and the terminal bias in volts, one gets an energy in eV.