The concept of "Global citizenship", which has become more and more important, based on the students' multi-focused individual development, has brought to the fore based on 21st century skills and has required appropriate educational environments for gifted students. In this context, the development of differentiated inquiry-based science lesson modules for gifted students will fill the current gap as it is important for the literature. The aim of this study is to examine the impact of differentiated inquiry-based science lesson modules for gifted students on the students' scientific process skills (SPS). As a method, the nature of the study was directed us to mixed nested patterns and developed three modules that applied to 16 gifted students in Science and Art Centers. In the evaluation process, we used "Diet Cola SPS test" as quantitative data source for pre and posttests. Also, we used observations in the implementation process and SPS activity reports filled out by students as qualitative data sources. As a result of data analysis, we found that SPS improved significantly (t(14)=-5.06, p<0.05). Accordingly, we have seen that this development in students is in basic and causal SPS, there is less development in experimental processes. We concluded that the gifted students needed more in depth and challenging activities in longer periods using modules like given in this study.