In general, dynamic ON-resistance testing is a measure of charge trapping phenomena in GaN power transistors. This publication describes the guidelines for testing dynamic ON resistance of GaN lateral power transistor solutions. The test methods can be applied to the following: a) GaN enhancement and depletion-mode discrete power devices [1] b) GaN integrated power solutions c) the above in wafer and package levels Wafer level tests are recommended to minimize parasitic effects when performing high precision measurements. For package level tests, the impact of package thermal characteristics should be considered so as to minimize any device under test (DUT) self heating implications. The prescribed test methods may be used for device characterization, production testing, reliability evaluations and application assessments of GaN power conversion devices. This document is not intended to cover the underlying mechanisms of dynamic ON-resistance and its symbolic representation for product specifications.