Organisasi didirikan dengan tujuan untuk mencapai visi dan misi organisasi tersebut. Dalam mencapai tujuan tentu terdapat pelaku organisasi. Hal ini berlaku juga dalam organisasi keagamaan, khususnya gereja GKI Rengasdengklok. Guna mencapai tujuan dari organisasi tersebut dibutuhkan perilaku OCB dari para pelaku organisasi tersebut. Menurut Organ (dalam Rahayu & Rozak, 2015) faktor yang paling dasar memengaruhi perilaku OCB adalah kepribadian, seperti Big Five Personality. Tujuan dari penelitian ini adalah mengetahui pengaruh dari parsial maupun simultan dimensi Big Five Personality terhadap OCB. Metode penelitian yang digunakan adalah kuantitatif. Subjek penelitian berjumlah 65 pengurus gereja GKI Rengasdengklok dengan pengambilan sampel menggunakan total sampling. Alat ukur yang digunakan adalah Organizational Citizenship Behavior Scale dan The Big Five Inventory. Uji analisa data menggunakan regresi berganda. Hasil hipotesis pertama menyatakan bahwa terdapat pengaruh extraversion, agreeableness, conscientiousness, neuroticism dan openness secara simultan terhadap OCB (R2 = .412, p <.05). Hasil hipotesis kedua menyatakan bahwa tidak terdapat pengaruh extraversion terhadap OCB (p>.05). Hasil hipotesis ketiga menyatakan bahwa tidak terdapat pengaruh agreeableness terhadap OCB (p>.05). Hasil hipotesis keempat menyatakan bahwa terdapat pengaruh conscientiousness terhadap OCB (p<.05). Hasil hipotesis kelima menyatakan bahwa tidak terdapat pengaruh neuroticism terhadap OCB (p>.05). Hasil hipotesis keenam menyatakan bahwa terdapat pengaruh openness terhadap OCB (p<.05). / The organization was founded with the aim of achieving the vision and mission of the organization. In achieving goals, of course there are organizational actors. This also applies to religious organizations, particularly the GKI Rengasdengklok church. In order to achieve the goals of the organization, OCB behavior is needed from the actors of the organization. According to Organ (in Rahayu & Rozak, 2015) The most basic factor influencing OCB behavior is personality, such as the Big Five Personality. The purpose of this study was to determine the effect of partial or simultaneous Big Five Personality dimensions on OCB. The research method used is quantitative. The research subjects were 65 activists of the GKI Rengasdengklok church. The samples were taken using total sampling. The measuring instrument used is the Organizational Citizenship Behavior Scale and The Big Five Inventory. Test data analysis using multiple regression. The results of the first hypothesis state that there is an effect of extraversion, agreeableness, conscientiousness, neuroticism and openness simultaneously on OCB (R2 = .412, p <.05). The result of the second hypothesis states that there is no extraversion effect on OCB (p> .05). The result of the third hypothesis states that there is no effect of agreeableness on OCB (p> .05). The results of the fourth hypothesis state that there is an effect of conscientiousness on OCB (p <.05). The results of the fifth hypothesis state that there is no effect of neuroticism on OCB (p> .05). The results of the sixth hypothesis state that there is an effect of openness on OCB (p <.05).