Brand evangelism is a strong type of word-of-mouth marketing with which consumers advise about goods or services to another. So a brand evangelist is a powerful marketing asset. There are many factors that effect brand evangelism or brand evangelists’ behaviour. Personality tratis are one of these factors that have strong effect on brand evangelism. Personality traits reflect consumer’s characteristic patterns of thoughts and behaviors. Personality traits are called as Big Five Model including extraversion, conscientiousness, neuroticism, agreeableness and openness. The main aim of this study is to determine the effect of Big Five Personality traits on brand evangelism. The other aim is to determine difference between men and women in terms of brand evangelism and personality traits. According to the results, extraversion and openness traits are more effective on brand evangelisim. So, openess and extraverted consumers may act as a brand evangelist than other consumers. Also, women have agreeableness, neuroticism, and conscientiousness traits more than men, and men have openness trait than women. In addition, there is no significant difference between them in terms of extraversion trait. Keywords: Extraversion, Conscientiousness, Neuroticism, Agreeableness; Openness, Brand Evangelism