Secure voltage adjustment techniques for computing systems and processing devices are presented herein. In one example, a method of controlling operating voltages for a processing device includes initializing a security portion of the processing device after application of input voltages to the processing device as supplied by voltage regulation circuitry according to voltage identifiers (VIDs) established for the processing device. The method includes, in the security portion, generating adjusted input voltages based on at least the VIDs and authenticated voltage offset information stored according to a digitally signed security process, and instructing the voltage regulation circuitry to supply the adjusted input voltages to the processing device.