Abstract: A messaging control system is described that is arranged to control the transmission of mobile messages—such as SMS messages—originating from third party content providers to user mobile devices. The messaging control system comprises a database for storing user preference data, a user interface to receive preference data from a user and a rules engine. The rules engine is arranged to receive a transmission request originating from a third party content provider to transmit a mobile message to the mobile device of the user. The rules engine is further arranged to transmit a response to the transmission request based on the outcome of a rules processing step identifying how the mobile message is to be handled.