Data synchronization policies

Techniques for data synchronization policies are described. In one or more implementations, techniques may be employed to set data synchronization ("sync") policies for devices in a data sync environment. The sync policies specify parameters for sync operations in the sync environment, such as how frequently data sync operations are performed, what types of data are synced to particular devices, how frequently particular types of data are synced, and so on. In implementations, the sync policies consider the number of devices that are participating in a sync environment and attributes of the devices in specifying parameters for sync operations. Data can be synchronized among devices in the sync environment based on the sync policies.