Passengers’ expectations of service quality at airports are becoming increasingly important as air traffic grows. This research investigated passengers’ perceptions of airport service quality at O.R. Tambo International Airport, South Africa. An existing model placing the concept of passenger expectations central to measuring an airport’s specific level of performance was applied. The results proved significant in terms of the investment made by the airport in staff training and highlighted areas for improvement. The results show that business travellers and leisure travellers have different opinions regarding the importance of services offered by airports and of the level of performance at ORTIA in particular. Significant differences also occur in the perceptions of frequent travellers and infrequent travellers.