The assessment of a child or adult who stutters should not be limited to the investigation of the individual’s disfluencies. Given the abundance of data indicating that stuttering is not solely a speech impediment, the constituents that surround stuttering need to be evaluated during the initial assessment. This paper presents information on an assessment battery for school-age children and one for adults, the Behavior Assessment Battery, which investigates the affective, behavioral and cognitive sequelae that frame the stuttering disorder. More specifically, the focus of this paper will be on the cognitive component of the stuttering syndrome, not only among school-age children and adults, but even among the very young, incipient stutterer. The internationally-based research on the KiddyCAT, CAT and BigCAT assessment tools is being summarized. In addition, the current status of studies on attitude toward communication of individuals in Japan is introduced.