The present disclosure pertains to systems and methods for monitoring a plurality of analog-to-digital converters. In one embodiment, a plurality of input channels may each be in communication with a different phase of a three-phase electric power delivery system. The input channels may be configured to receive analog signals from the different phases. A composite signal subsystem may be configured to generate a composite signal based on the plurality of input channels. An analog-to-digital converter subsystem may be configured to produce a digitized representation of each of the plurality of input channels and a digitized representation of the composite signal. An analog-to-digital converter monitor subsystem may identify an error in the analog-to-digital conversion based on the digitized representation of the composite signal and the digitized representations of the plurality of input channels.