Nowadays, one of the most important problems encountered in business life is loneliness. Because of the resasons such as rise in competition and focusing on career development, besides, organizations cause work life imbalance caused by increasing the work load of the employees instead of increasing the employment the concept of loneliness at work is confronted as an important reality. Nevertheless, one of the topics that are considered in business life is the determination of people's personalities. One of the functions of assessment of personality is to determine the characteristics and diversity of individuals who are not alike. Because, organizations employ their workers by observing their personality differences and hire them in appropriate positions In other words, one of the most important resources of business is people. Businesses are investing in people to gain competitive advantage. In this context, businesses prefer employees who can move with unity and cooperation, have high motivation, social, have strong communication, hard working and responsible personality instead of employees who are lonely at work. Therefore, nowadays, personality assessment and loneliness in business life are the agenda. For this reason, in this study the effect of the five factor personality on the loneliness at work wil be investigated. In this regard, in the literature section of this study, personality, five factor personality and it’s dimensions, concept of loneliness at work and it’s dimensions will be discussed. For this purpose the research conducted on 306 white collar employees who work in six different legally online betting vendor companies that operates in Turkey. According to the research results, negative relationship between four personality factors which are conscientiousness, extraversion, agreeableness and openness is examined with loneliness at work; and positive relationship with neuroticism and loneliness at work is witnessed.