Analogical reasoning is both an innate ability and a basic learning mechanism that can be improved. In classrooms, it is an important tool used by teachers, especially when explaining difficult or abstract issues. In addition to its use in all aspects of our lives, analogical reasoning is commonly used in textbooks. This research examines the extent to which analogies are used in high school science textbooks, the subjects of the examination being high school physics, chemistry, and biology course textbooks used by students between 14 and 17 years of age. A total of 15 textbooks (four biology books, five physics books, and six chemistry books) were reviewed. Ninety-two analogies were identified in these books. These analogies were classified based on a scheme developed by Curtis and Reigeluth. Findings are discussed in the context of previous related studies.