Past research has shown that rapport and cooperation between individuals is related to the level of nonverbal synchrony they achieve in their interactions. This study investigates the extent to which staff and clients with mild to borderline intellectual disability achieve interactional synchrony in daily social interactions. Whilst there has been work examining how staff can adapt their verbal communication to help achieve better mutual understanding, there has been an absence of work concerning the responsiveness of staff and clients regarding their nonverbal behavior. Nineteen staff members video-recorded a social interaction with one of their clients in which the client had a need for support. The recordings were analyzed using cross recurrence quantification analysis. In addition, fifteen staff members as well as clients with an intellectual disability completed a questionnaire on the quality of the nineteen video-recorded interactions. Analysis of the nonverbal patterns of interaction showed that the staff-client dyads achieved interactional synchrony, but that this synchrony is not pervasive to all nonverbal behaviors. The client observers appeared to be more sensitive to this synchrony or to value it more highly than the staff raters. Staff observers were sensitive to quantitative measures of talking. The more staff in the interactions talked, the lower the quality rating of the interaction. The more the clients talked, the more positively the staff observers rated the interactions. These findings have implications for how collaborative relationships between clients and support workers should be understood. © 2013 Springer Science+Business Media New York.