Textbooks are a prominent part of science teaching and learning. For science teachers and students, textbooks are the major source of information for planning and classroom practice. In addition to the content of textbooks, are end-of-chapter questions that should consolidate students learning and enhance their thinking processes. Therefore, this study adopted the framework of the revised Bloom's Taxonomy to classify and analyze end-of-chapter questions from three chemistry textbooks used in Nigeria. The results from this study indicated that majority (76%) of the questions were at the lower order of ("understand," "remember," and "apply"), while 46% and 32% measure "conceptual" and "procedural" knowledge respectively. The results further revealed that the number of questions in the categories of evaluate and create differs significantly at, F (5, 1744) = 5.61, ? < 0.01, from the other categories of the cognitive process skills. The following conclusions were drawn: "understand" and "analyze" categories recorded the highest number questions in the cognitive objectives; and there was no metacognitive questions. Implications for textbook authors and teachers were discussed.