The present study investigated the impact of personality traits on employee performance in a moderating affect of organizational culture. Personality traits taken were Introversion and Extroversion. Sample size of the study was 100 employees from different government institutions of Islamabad, Pakistan. Data was gathered through survey. It was hypothesized that personality traits are positively related to employees' performance, furthermore organizational culture shows moderating impact between personality traits and performance. The results indicated that there is a significant impact of personality traits on employees, performance and have varying value depending upon the culture of the organization.