An antenna monitoring system includes a cloud based server, and sensor devices, with each sensor device including a portable housing to be mounted on a respective directional antenna, and at least one alignment sensor carried by the portable housing and configured to sense alignment of the respective directional antenna. Each sensor also includes a cellular telephone transceiver carried by the portable housing, and a controller carried by the portable housing, and configured to collect alignment data from the at least one alignment sensor, and communicate with the cloud based server via the cellular telephone transceiver. The cloud based server may include a processor and a memory coupled thereto and configured to provide at least one user interface associated with the alignment data for the sensor devices.