The general purpose of this study is to investigate the client-counsellor interaction in the psychological counseling process at the verbal behavior level. The study also aims to analyze the relationship between the behaviors observed in the process with both clients and counsellors' evaluations of sessions and whether changes were observed in clients' lives and behaviors after psychological counseling. The data were collected from 69 senior students in a Department of Psychological Counseling and Guidance in Turkey and from the same number of clients to whom they provided counseling services. The partial sampling method was used because smaller sampling was needed in order to describe successful and unsuccessful therapeutic processes in a more detailed way. The study made use of the "Psychotherapy Interaction Coding System," "Session Satisfaction Scale," and " Changes in Life and Behaviours Scale." Results show that psychological counsellors' display of empathetic and supportive type behaviors are dependent on the participation or cooperation of the client. Both clients and counsellors' satisfaction levels concerning the sessions demonstrated a significant relationship. Moreover, clients and the psychological counsellors' satisfaction levels concerning sessions were positively associated with some of the behaviors that they demonstrated during the process. In terms of the criterion, "changes in life and behaviors," successful and less successful group session satisfaction was found to differ in terms of a number of behaviors displayed during the process. The counsellors in the successful group showed more empathetic and supportive behaviors than the counsellors in the unsuccessful group. While counsellors in the successful group expressed their emotions, informed about changes, and demonstrated participation/cooperation more frequently, they demonstrated less inhibitive type behaviors, which were found to negatively affect the process.