Methods, apparatus, and processor-readable storage media for automated detection of unauthorized access to device screens using machine learning facial recognition techniques are provided herein. An example computer-implemented method includes automatically detecting, using one or more machine learning facial recognition techniques, at least a portion of at least one face within a given proximity of a user device; automatically performing a comparison, using one or more machine learning facial recognition techniques, of the detected portion of the at least one face with facial images attributed to a set of trusted individuals; and automatically performing security-related actions with respect to the user device upon determining, based at least in part on the comparison, that the detected portion of the at least one face exhibits at least a threshold level of distinctiveness relative to each of the facial images attributed to the set of trusted individuals.