Abstract. Counterproductive work behavior is a phenomenon that is commonly found in various organizations and constitutes a major issue in the workplace due to its potential to disrupt and harm the organization. Counterproductive work behavior refers to deliberate behavior intended to harm the organization and individuals within it (Spector et al., 2006). Counterproductive work behavior may emerge as a result of workplace ostracism (Zappalà et al., 2022). The competitive culture within academic institutions may contribute to cases of ostracism, particularly among faculty and staff who may feel excluded within their respective faculties (Litzellachner et al., 2024). This study aims to examine the extent to which workplace ostracism contributes to counterproductive work behavior. This is a non-experimental quantitative study using a cross-sectional design and simple linear regression analysis. The study involved 160 university support staff members at a private higher education institution (PTS X) in Bandung. The sampling technique employed was convenience sampling. The instrument used to measure workplace ostracism was the Workplace Ostracism Scale developed by Ferris (2008), and counterproductive work behavior was measured using the Counterproductive Work Behaviour-Checklist developed by Spector et al. (2006). The first finding shows that workplace ostracism has a significant positive contribution to counterproductive work behavior toward the organization (CWB-O), contributing for 35.7% among the university support staff of PTS X in Bandung. The second finding reveals that workplace ostracism has a significant positive contribution to counterproductive work behavior toward individuals (CWB-P), contributing for 53.1% within the same group. Abstrak. Counterproductive work behavior merupakan fenomena yang sangat mudah dijumpai di berbagai organisasi dan merupakan masalah utama di tempat kerja yang memiliki kecenderungan mengganggu dan membahayakan organisasi. Counterproductive work behavior merupakan perilaku yang disengaja untuk merugikan organisasi dan orang-orang di dalamnya (Spector et al, 2006). Counterprodtive work behavior dapat muncul diakibatkan oleh workplace ostracism (Zappalà et al, 2022). Budaya kompetitif lembaga akademis dapat berkontribusi pada kasus ostracism terutama pada fakultas dan staf yang mungkin merasa tersisih di fakultas masing-masing (Litzellachner et al., 2024). Penelitian ini bertujuan untuk mengetahui seberapa besar kontribusi counterproductive work behavior terhadap workplace ostracism. Penelitian ini merupakan penelitian kuantitatif non eksperimental dengan desain cross-sectional dan menggunakan analisis regresi linear sederhana. Penelitian ini melibatkan 160 tenaga pendidik PTS X di Kota Bandung. Teknik sampling yang digunakan adalah convenience sampling. Alat ukur yang digunakan untuk mengukur workplace ostracism adalah Workplace Ostracism Scale yang dirancang oleh Ferris (2008) dan Counterproductive Work Behaviour-Checklist yang disusun oleh Spector et al (2006) untuk counterproductive work behavior. Hasil pertama menunjukkan bahwa workplace ostracism memiliki kontribusi positif signifikan terhadap CWB-O sebesar 35,7% pada tenaga pendidik PTS X di Kota Bandung. Hasil kedua menunjukkan bahwa workplace ostracism memiliki kontribusi positif signifikan terhadap CWB-P sebesar 53,1% pada tenaga pendidik PTS X di Kota Bandung.