Science textbooks play an important role in making scientific knowledge and applications available to learners. In most countries, science curriculum expects to cultivate scientifically literate individuals who are able to use science process skills. Critical analysis of textbooks is therefore crucial to determine whether they can facilitate this outcome. The purpose of this study is to find out to what extent science process skills are included in the activities of elementary and middle school science textbooks in Turkey. A total of 304 activities in six science textbooks were analyzed. A content analysis was employed to determine the frequency and percentage of science process skills in the activities. The results indicate that observing, collecting information and data, recording data, and interpreting and drawing conclusions receive the most emphasis in the activities at all grade levels. Measuring, estimating, predicting, processing and model creating, determining variables, knowing and using experimental materials and tools, and designing experiments are either the least frequently found science process skills or are included in none of the activities. This suggests textbooks focus more on basic science process skills rather than on high-level, causal, and experimental skills. [Note: The issue number (12) shown in the header on the PDF is incorrect. The correct issue number is 13.]