While there is a burgeoning of short-term research in self, peer, and teacher assessment, there is a paucity of longitudinal studies in this kind of assessment. Furthermore, oral assessment in English as a foreign language (EFL) context is relatively underexplored. The current study was designed to investigate the reliability and validity in 30 oral presentations that spanned over a period of four months, including variables such as the students' gender, ability, and the topic of presentations. The results indicated that reliability indices of all 30 oral assessments were high, ranging from 0.70 to 0.95 as measured by Cronbach Alpha. In addition, validity indices improved over time, with the later presentations enjoying higher validity indices than the preceding ones. The gender of the assessors did not affect the total mean score of the presentations. Also, students' self-assessments were not significantly different from the scores of the teacher, although they appeared slightly higher. There was no significant correlation between self-assessment and teacher-assessment.