ISO 15118 Road vehicles -- Vehicle to grid communication interface is a proposed international standard defining a vehicle to grid (V2G) communication interface for bi-directional charging/discharging of electric vehicles (EVs). The standard provides multiple use cases like secure communication, smart charging and the Plug & Charge feature used by some electric vehicle networks.

ISO 15118 is one of the International Electrotechnical Commission's (IEC) group of standards for electric road vehicles and electric industrial trucks, and is the responsibility of Joint Working Group 1 (JWG1 V2G) of IEC Technical Committee 69 (TC69) together with subcommittee 31 (SC31) of the International Organization for Standardization's (ISO) Technical Committee 22 (TC22) on road vehicles.

ISO and IEC began working together on the standard in 2010, and a Plug & Charge section was released in 2014. No automakers had a productive implementation of the standard by 2018.^{[needs update]}

The Plug & Charge feature envisioned by ISO 15118 enables an electric vehicle to automatically identify and authorize itself to a compatible charging station. This makes it convenient for the driver, to receive energy for recharging the vehicle's battery. The only action required by the driver is to plug the charging cable into the EV and/or charging station, because the car and the station identify each other by exchanging public key certificates to facilitate payment. An open test system accessible through the internet was launched in November 2021. The proposed standard can be used for both wired (AC and DC charging) and wireless charging for electric vehicles.

Some 2021 model year EVs support the Plug & Charge standard, including the Porsche Taycan, Mercedes-Benz EQS, Lucid Air, and Ford Mustang Mach-E. Model year 2024 EVs include BMW i4, BMW i5, BMW i7, BMW iX, Hyundai Ioniq 5 and Hyundai Ioniq 6.

Other manufacturers such as Volkswagen updated their ID family vehicles (such as the ID.4 and the ID.5) to support Plug & Charge. Some cars need hardware updates.

All Tesla vehicles since 2012 (before the release of ISO 15118-2 in 2014) have a proprietary version of Plug & Charge. Other proprietary solutions exist, such as those developed by Paua.

Besides Tesla, alternatives to Plug & Charge exist including "Autocharge", which is based on DIN Spec 70121 (Combined Charging System - CCS) using the car's fixed MAC address. For the end-user, the functionality is similar but tied to the specific operator and their charging rates. Autocharge has been used for many years i.e. at the charging stations of Fastned and lately of Voltrelli. In the market, Autocharge is considered a less secure mechanism than Plug & Charge because of the missing certificate chain. Cars from the Volkswagen Group even have had a software update to 'break' this functionality. While Autocharge worked flawlessly at the launch of the ID.3 model, Volkswagen switched to variable MAC addresses and therefore these cars no longer be used with Autocharge. Some say this is for commercial reasons because the Volkswagen Group heavily invested in Plug & Charge. If Autocharge would become a big success then the need for the development of Plug & Charge would be minimized.