Educational assessment can be a powerful tool in enhancing classroom instruction and student performance. Yet, its effectiveness relies on the beliefs and knowledge of those who apply it on a daily classroom basis. This study explored attitudes, competence, knowledge, and practices of teachers about educational assessment. Participants were 165 in-service teachers teaching various subject areas in grades 5 to 10 randomly selected from Muscat educational governorate in the Sultanate of Oman. The study employed a descriptive survey research design. Results revealed that although teachers held a favorable attitude towards and perceived themselves as being competent in educational assessment, they demonstrated a low level of knowledge in educational assessment. Teachers used a variety of assessments in the classroom primarily for assigning grades and motivating students to learn, with some variations by gender, grade level, and subject area. Teaching load and teaching experience accounted for some of the variations in teachers' educational assessment practices. Implications for professional development of teachers in educational assessment as well as recommendations for future research were discussed.