According to some example embodiments, systems, apparatus, methods, computer readable media, and computer program products are provided for implementing a wireless shelf pusher activity detection system. One example apparatus is a monitoring device for monitoring theft or sales activity associated with a product pusher device. The monitoring device may include a sensor configured to detect movement of a pusher member of the product pusher device, a wireless communications interface, and a processor. The processor may be configured to receive at least one sensor signal from the sensor indicating movement of the pusher member, determine a product movement activity type based on characteristics of the at least one sensor signal, and generate, for transmission via the wireless communications interface, a pusher activity message indicating the product movement activity type.