This study builds on a previous pilot study conducted by Alkharusi, Aldhafri, Alnabhani, and Alkalbani (2012) to explore educational assessment attitudes, competence, knowledge, and practices of in-service teachers in the Sultanate of Oman. The present study extends the previous pilot study by surveying a larger sample of in-serivce teachers teaching grades 5 to 12 in all educational governorates in the Sultanate of Oman as opposed to 165 in-service teachers teaching grades 5 to 10 in one educational governorate. Specifically, the study aimed at developing a profile of educational assessment attitudes, competence, knowledge, and practices for teachers in the Sultanate of Oman. The profile was developed as a function of teachers’ gender, nationality, educational governorate, teaching grade, qualification, teaching subject, pre-service assessment training, in-service assessment training, teaching load, and teaching experience. The study employed a descriptive survey research design. Participants were 3557 in-service teachers teaching various subject areas in grades 5 to 12 randomly selected from all educational governorates in the Sultanate of Oman. Confirming Alkharusi et al. (2012) study, findings of the current study showed that the teachers tended to have a positive attitude towards educational assessment. Despite their perception as being competent in educational assessment, they demonstrated a low level of the educational assessment knowledge. Further, the teachers indicated using different classroom assessments mainly for grading and increasing students’ desire for learning. Teaching load and teaching experience explained some of the differences in the teachers’ educational assessment profile. Also, the educational assessment profile varied as a function of the selected demographic and background variables. The findings pointed to a conclusion that professional educational assessment programs for teachers should be continued and tailored to the needs and nature of the teachers’ classroom realities. Future research is needed to judge the validity of the teachers’ self-report surveys concerning educational assessment.