Events are crucial for development of destinations across different parts of the world since they possess important social, cultural, and economic outputs. International celebrity events provide additional destination attraction and they create a sustainable tourism industry across many parts of the world. Despite research in recent times in events gaining tremendous interest among scholars and emerging as a crucial area of study, little is known on how international celebrity events hosting influences tour firms' performance. This study explored the role of international celebrity events destination promotion on tour firms' performance in Nairobi City County, Kenya. A cross-sectional research design was adopted for the study. The sample size of the study constituted of 390 managerial employees who were drawn from all the 329 tour firms registered with the Kenya Association of Tour Operators. Stratified, systematic, purposive, and convenient sampling approaches were used to sample the respondents, while questionnaires and interview schedules were used for collection of data. Results showed that the international celebrity events destination promotion depicted a positive and statistically significant relationship with tour firms performance (p=0.000<0.05). The study recommends development and hosting of special international celebrity events in the country by event organizers as the basis of increasing the competitiveness of Nairobi City County as a preferred tourist destination.