It said handsets would have a micro USB interface, already used to transfer pictures from digital cameras to a computer.
The initial group of companies that have signed for the change include Nokia, LG, Motorola, Samsung and Sony Ericsson.
Operators such as AT&T, Orange, Telefonica, T-Mobile and Vodafone are also part of the initiative.
The GSMA said that eventually it expected mobile phones to ship without a charging plug and cable because everybody would have one.
This should also lead to less waste and could yield energy savings because the agreement calls for chargers to meet efficiency targets, the group said.
(Reporting by Niclas Mika; Editing by David Cowell)