The aim of this study was to investigate the extent to which science process skills are represented in the texts and activities in the 3rd, 4th, 5th, 6th, 7th, and 8th grade science textbooks according to the learning areas in the science curriculum. This study was carried out by document analysis method. Course contents and activities in science textbooks were analyzed using descriptive analysis. Results showed that total of 899 science process skills are identified in the 3rd, 4th, 5th, 6th, 7th, and 8th grade science textbooks covering total 42 units. In addition, when the averages of science process skills use in science textbooks are examined, it has been determined that the use of science process skills in 6th (%23.9) and 7th (%18.8) grade textbooks is above the average. While the use of science process skills in science textbooks increases from the 3rd grade to the 4th grade at primary education level, the similar increase is not determined in the use of science process skills in secondary education science textbooks. Moreover, it is found that science process skills are mostly focused on the 6th grade science textbook (n=215) and the least in the 3rd grade science textbook (n=112). As a result, when science textbooks are evaluated according to grade levels in terms of science process skills, it is determined that the most common science process skill identified is observing, and the least used one is the using data and modelling.