The main purpose of the study was to investigate the effects of personality traits on employee’s job performance; gender as a moderator, in selected bureaus of Amhara National Regional State, Bahir Dar city. The study used quantitative research approach and explanatory research design to objectively answer the proposed research questions. Simple random sampling technique was used to select the six bureaus from the total of 20 bureaus and also proportionate stratified sampling technique was adopted to treat the 260 participants; and out of those, 245 has responded. Descriptive analysis, Pearson correlation, analysis of variance (ANOVA) and multiple regressions were carried out to analyze the data using SPSS version 23. Regression analysis was used to investigate the effects of personality traits on employee’s job performance and gender as a moderator on relationship of personality traits and job performance. The descriptive result of the study shows that the mean score of each individual independent variable is above 3.4832. The results of the regression analysis model indicated that the five independent variables (openness to experience, conscientiousness, extraversion, agreeableness, and neuroticism) explain about 62.3 percent of the variation in the level of job performance. Based on the findings, the study recommends during recruitment and selection the human resource managers should not only concentrate on academic qualifications and experience, but also they should take into consideration the personality of applicants in order to assign the right people for the right job.