This paper discusses the levels of The Instructional Model for Using History of Science (UHOS) to explain the relationship between the history of science and science teaching. The UHOS model proposes four levels: Conceptual Level, Epistemological Level, Sociocultural Level, and Interest Level. Each Level has sublevels with regards to types of historical knowledge, pedagogical approach and educational objectives. The UHOS model purports to help educator and researchers to explain their findings with an overarching theoretical framework.