Master's Thesis from the year 2019 in the subject Psychology - Social Psychology, grade: Very Good, Addis Ababa University (School of Psychology), course: Thesis, language: English, abstract: Organizations are paramount places to observe human behavior. Principally, when it comes to organizational citizenship behavior, the ultimate understanding is residing inside work establishments. The present study was dedicated to discerning the interconnections between employees extra-role behaviors and factors behind the realization of these actions. Based on that, the due emphasis was given to see the prediction capability of socio-demographic characteristics of employees, Organizational identification, Job involvement, Organizational justice dimensions on employees OCB & its dimensions in the Secretariat of the Ethiopian Parliament, as it is one of the major government organizations. The study followed a quantitative approach with correlational design. The data were collected using standardized measurement scales by taking 202 (N=417) employees as participants through probability sampling assumptions. The collected data were analyzed using descriptive and inferential statistics corresponding Percentage, Mean, Man-Whitney & Wilcoxon tests, Pearson's Product Moment Correlation, MANOVA, Regression Analysis as well as Canonical Correlation Analysis. Giving that, participants did not generally vary by their socio-demographic characteristics in displaying OCB, but with the exception of their Age groups and Educational status to show Altruism & Conscientiousness patterns respectively. Work experience was also relatively a good predictor of employees overall OCB level. Organizational identification of employees was significantly correlated with overall OCB and Altruism, Conscientiousness, Courtesy & Civic-virtue dimensions; Job involvement was also significantly correlated with OCB & all the five dimensions; from Organizational justice dimensions, distributive