The main purpose of this research is to analyse the effect of the loneliness status of principals' working at the schools in Aydin, Turkey to their individual performance. The partcipants included 286 principals, working in Aydin city center, district or villages. "Loneliness at Work Scale" (LAWS) and "Employee Performance Scale" (EPS) were used as data collection tools. According to the findings, principals' performance level is high; the principals suffer from loneliness in the medium level when the social relationship dimension of Loneliness at Workplace Scale is considered and in the low level when the emotional deprivation dimension and the total scores received from the scale are considered. According to the hierarchical regression analysis, it was observed that "total working years as principal at current institution, the socio-economic status of the school, the manner of placement as principal and the total working years as principal" predict the performance scores significantly. As a result it can be stated that rather than the personal characteristics as age, gender, length of service, it should be highly considered that organizational factors and environmental factors (socio-economic status, cultural patterns etc.) are more important.