Higher education institutions have switched from the traditional paper-based assessment to online assessment in the last decade, and it is worthwhile to examine how the users have perceived such a change. While many technology acceptance studies focused on students as participants, this study examines the lecturers' perception of online assessment. The Unified Theory of Acceptance and Use of Technology model (UTAUT) has been widely adapted for technology acceptance studies, and it is suitable for the study on online assessment systems. Unlike the findings from the original UTAUT model, performance expectancy did not have a significant effect on behavioral intention. A new relationship was found between Social Influence and Use Behavior. The UTAUT was extended with Usability, Learnability and Attitude as additional constructs. An essential aspect of this study ascertained that attitude, a construct that was absent in the original model, has a significant effect on behavioral intention.