This special issue brings together studies representing the current state of the art research on inhibited reactive attachment disorder (RAD) from developmental psychology and developmental attachment research. This editorial introduces and discusses conceptual topics of the development and the assessment of inhibited RAD. Next, five empirical studies of this special issue cover timely topics from developmental trajectories and longitudinal stability of RAD to associations with caregiving experiences in institutions, IQ, and psychopathology, moreover aspects of internal working models of children with inhibited RAD are examined. The commentary meta-analytically integrates the empirical evidence of all five studies and offers theoretically derived suggestions for further research. In this editorial, we discuss unsettled issues and future directions for attachment oriented research in this field.