This research probed the perceptions of secondary school science teachers concerning the objective and utility of assessment, exploring the influences of gender, teaching experience, and specific science subject components. A total of 100 secondary school teachers from Selangor participated in the study, completing the Teacher's Conception of Assessment (TCoA) online questionnaire. This instrument comprised 27 statements categorized into four key aspects: Improvement, Irrelevance, School Accountability, and Student Accountability. Interestingly, the data revealed that the highest mean score was attributed to the irrelevance of assessments (M=4.44; SD=0.86), followed by assessment for improvement (M=4.21; SD=0.95), student accountability (M=4.18; SD=1.32), and lastly, school accountability (M=4.15; SD=1.44). A closer examination of the data pointed towards significant gender-based differences in teachers' perceptions of institutional accountability and educational enhancement through assessments, with female and male teachers scoring higher in these respective areas. However, the length of teaching experience did not appear to significantly affect the teachers' perceptions across any of the assessed parameters. There were noteworthy differences in teachers' perceptions of student accountability in assessments when evaluated based on the subject taught, with Biology teachers reporting higher mean scores as compared to Chemistry and Physics teachers. Additionally, teachers' perceptions regarding the improvement role of assessments and their irrelevance differed significantly across subjects, with general science teachers attaining higher mean scores than Chemistry, Biology, and Physics teachers. The findings of this study shed light on teachers' understanding of assessment, particularly in the field of Science, and serve as a valuable resource for all educational stakeholders. By understanding teachers' perceptions, policymakers and school administrators can make informed decisions that would potentially enhance teaching and learning processes.