Therapeutic relationships are created and maintained through interaction, and so the way that talk, posture, and gesture are managed within clinical interactions provides one way to understand the nature of these kinds of relationship. The communicative interaction skills of clinicians can be seen as part of their essential tool kit, as these skills provide the medium through which therapy is conducted. This chapter will focus on interactions where the clinician needs to establish a therapeutic relationship with more than one person, as this situation presents specific challenges to the management of the clinical interaction. The chapter will explore two commonly encountered multiparty interactions: assessment through case-history interview when the client is accompanied by a family member, and group therapy. The nature of the clinical linguistic proficiency needed within these interactions will be explored through the analysis of case examples, making use of methodologies developed for the purpose of investigating interaction, namely conversation and discourse analysis. The implications of understanding the interactive achievement of therapeutic relationships for skill development will also be discussed.