Today, the world confronts many natural resource-based issues. However, endeavors from the government and non-government organizations to help solve these problems still remain inadequate. There is a fierce cry to go down at the very roots of the problem---the low level of knowledge on natural resource-based education. Textbooks are among the main instructional materials in educational systems. However, there is a question on whether the school textbooks are being used as an opportunity for increasing the awareness among the young and mobilizing them into action. Hence, this research was conducted. In this study, content analysis was used to assess the frequency of occurrence and presentation of Natural Resource Management (NRM) themes in English textbooks of public high schools. Tallies on the occurrence of the NRM themes and their presentations were done manually. Results showed that Natural Environment Conservation theme had the highest occurrence in English textbooks among all NRM themes. Further, the presentation of themes was mostly in the form of paragraphs. Findings showed that the analyzed textbooks contained only few articles with NRM themes and the presentation of these themes were less variable. It is desirable that these textbooks carry more NRM themes to substantiate their roles of creating awareness on NRM education among the students.