[Penelitian ini bertujuan untuk mengetahui adanya pengaruh komunikasiinterpersonal terhadap efektivitas tim pada karyawan di unit Corporate Human Resources (CHR) PT KLM. Berdasarkan hasil identifikasi masalah, diketahui bahwa komunikasi interpersonal antar anggota tim pada unit CHR masih belum efektif, dimana hal ini menjadi salah satu faktor yang membuat efektivitas tim belum dapat tercapai. Asumsi tersebut selanjutnya dibuktikan dengan mengukur pengaruh dari komunikasi interpersonal terhadap efektivitas tim, dengan menggunakan Parker’s Team Development Survey (Parker, 2008) dan Interpersonal Communication Questionnaire (DeVito, 1989) yang telah diadaptasi ke dalam Bahasa Indonesia. Responden penelitian ini berjumlah 51orang karyawan unit CHR yang memiliki jabatan sebagai Staff/Officer dan Supervisor/Superintendent. Hasil uji regresi menunjukkan bahwa komunikasi interpersonal terbukti secara signifikan memiliki pengaruh terhadap efektivitas tim (r = 0.74; R2 = 0.55; p < 0.05). Hal tersebut berarti bahwa adanya peningkatan pada komunikasi interpersonal antar anggota tim akan dapat meningkatkan efektivitas tim. Intervensi untuk meningkatkan komunikasi interpersonal antar anggota tim dapat dilakukan melalui team training mengenai komunikasi interpersonal yang efektif di dalam tim (team communication training). Padapenelitian ini, adanya dampak dari team communication training terhadap komunikasi interpersonal dan efektivitas tim masih belum dapat dibuktikan, karena intervensi team communication training yang tidak dapat diimplementasikan.;The aim of this study was to determine the effect of interpersonal communication on team effectiveness of employees in Corporate Human Resources (CHR) unit of PT KLM. The results of the problem identification showed that interpersonalcommunication among the team members on this unit was still not effective, and it was considered as the factors that make the team effectiveness could not be achieved. This assumption then proven by measuring the impact of interpersonal communication on the team effectiveness using the adaptation of Parker’s Team Development Survey (Parker, 2008) and Interpersonal Communication Questionnaire (DeVito, 1989). A total of 51 employees from CHR unit wereparticipated as respondent in this study. The simple regression analysis result indicated that interpersonal communication has proven to significantly affect team effectiveness (r = 0.74; R2 = 0.55; p < 0.05). Therefore, the interventions to improve interpersonal communication between team members can be conducted through team training related to effective interpersonal communication within theteam (team communication training). Unfortunately, this study could not proved the impact of team communication training to interpersonal communication and team effectiveness, because the intervention could not be implemented., The aim of this study was to determine the effect of interpersonal communicationon team effectiveness of employees in Corporate Human Resources (CHR) unit ofPT KLM. The results of the problem identification showed that interpersonalcommunication among the team members on this unit was still not effective, andit was considered as the factors that make the team effectiveness could not beachieved. This assumption then proven by measuring the impact of interpersonalcommunication on the team effectiveness using the adaptation of Parker’s TeamDevelopment Survey (Parker, 2008) and Interpersonal CommunicationQuestionnaire (DeVito, 1989). A total of 51 employees from CHR unit wereparticipated as respondent in this study. The simple regression analysis resultindicated that interpersonal communication has proven to significantly affect teameffectiveness (r = 0.74; R2 = 0.55; p < 0.05). Therefore, the interventions toimprove interpersonal communication between team members can be conductedthrough team training related to effective interpersonal communication within theteam (team communication training). Unfortunately, this study could not provedthe impact of team communication training to interpersonal communication andteam effectiveness, because the intervention could not be implemented]