Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for implementing mobile device-based bandwidth throttling. In one aspect, a method includes receiving policy from a wireless carrier that specifies one or more data usage thresholds allotted by the wireless carrier for data transferred over a wireless carrier network during a predetermined period of time, determining an amount of data that has been transferred by the mobile device over the wireless carrier network during the predetermined period of time, determining that the amount exceeds one or more of the data usage thresholds, and throttling the bandwidth of a mobile device over the wireless carrier network based on determining that the amount exceeds one or more of the data usage thresholds.