Background: Nature of Science (NOS) is defined to be the epistemology of science, and comprised of distinctive defining aspects. The representation of these NOS aspects in school science textbooks is likely to affect how students understand NOS. Representation of NOS aspects can differ between topics even within the same textbook and these topical differences may shed light on the different improvements required for a progressive and more balanced representation of NOS aspects. Purpose: This study aims to (1) analyse the representations of NOS aspects in Singapore biology textbooks; (2) identify and discuss topical differences in the representation of NOS aspects; and (3) suggest some ways to improve NOS representation in textbooks. Method: Three Singapore secondary school biology textbooks were analysed for their representations of 11 key NOS aspects using a document analysis approach. Textual material was coded into discrete categories in a topic-by-topic manner independently by two coders. Results: Informed statements regarding NOS aspects were predominantly implicit in nature. High scores for eight NOS aspects were obtained in one textbook incorporating experimental work in many chapters to support and illustrate scientific concepts. High scores for the creative NOS and the nature for scientific theories were scored in another textbook that was found to utilise History of Science to provide a context for presenting scientific information. Topics with consistently low NOS representations were predominantly presented in a descriptive, factual manner, while topics with consistently high scores generally approached the topics by discussing the historical development of knowledge. Conclusions: Using experimental work to present scientific knowledge and discussions of the historical development of scientific knowledge are both effective approaches to represent many NOS aspects well in a textbook. These two approaches can be used in combination in a textbook in order to further improve NOS representation and overcome the individual limitations of each approach.