This paper examines the crucial role of Natural Sciences (NS) within the secondary education curriculum, emphasizing its importance in cultivating and expanding students’ scientific knowledge at the lower secondary level. Additionally, it concentrates on the creation of an assessment tool for evaluating students’ NS learning competencies, through the analysis of prior research and the application of suitable assessment criteria. The proposed approach within this paper provides a thorough and effective method for assessing students’ comprehension and abilities in NS, thus improving the quality of science education in secondary schools.