A Time-Based Service Monitoring mechanism for monitoring Service Level Agreements (SLAs) over specific time intervals is described. To provide for the time-based monitoring of service, data is received for defining one or more tests for monitoring the level of network service that is being provided to a particular customer. Based on the received data, information is created and stored that defines a specific time range for when the one or more tests are to be enforced. The one or more tests are distributed to one or more agents that are configured to communicate with devices that are associated with the network. The devices are then configured to perform the one or more tests within the specific time range. Based on the results, the customer is provided information indicating whether they are receiving the level of service that has been guaranteed by the service provider over the specific time intervals.