Purpose: Despite the increasing attention of organizational commitment in the management literature, most studies predominantly focus on full-time workers in traditional work settings. This paper examined the antecedents of organizational commitment among casual academics working in the tertiary education sector in Australia. Design/methodology/approach: A questionnaire survey was developed and distributed to casual academics working in a large Australian public university. Findings: Analysis of the data shows that personal characteristics (gender, marital status, family responsibilities and education), job-related characteristics (supervisor support, co-worker support, role clarity and resource availability) and job involvement characteristics (tenure, second job and post-graduate study at the employing university) all impact on organizational commitment. Research limitations/implications: Australian tertiary institutions are prominent employers of casual workers, however, very little is known about the work behavior of this group of academics. The results of this study highlight important directions for implementing strategies to increase casual academic's organizational commitment. Organization commitment is important because it is known association with other important organizational variables such as turnover, absenteeism and work effort. Originality/value: Given the increasing reliance on casual academics in tertiary institutions, this study provides the first step in better understanding the factors that affect the organization commitment of casual academics. (Contains 7 tables and 1 figure.)