Project Ara was a modular smartphone project under development by Google. The project was originally headed by the Advanced Technology and Projects team within Motorola Mobility while it was a Google subsidiary. Google retained the ATAP group when selling Motorola Mobility to Lenovo, and it was placed under the stewardship of the Android development staff; Ara was later split off as an independent operation. Google stated that Project Ara was being designed to be utilized by "6 billion people": 1 billion current smartphone users, and 5 billion feature phone users.

A modular smartphone is a smartphone designed for users to upgrade or replace components and modules without the need for resoldering or repair services. The most important component is the main board, to which others such as cameras and batteries are attached. Components can be obtained from open-source hardware stores.