The purpose of this research is to examine the relationship among sixth-, seventh-, and eighth-grade gifted students' spatial reasoning skills, conceptual understanding of basic astronomy topics, and science achievement. To achieve this, the study was designed as a multi-factor predictive correlational study. The research sample consists of 642 gifted middle school students enrolled in Science and Art Centers across 12 cities in Turkey. Data were collected using the Conceptual Understanding of Basic Astronomy Subjects Test, the Mental Image-Focused Spatial Reasoning Skill Test, and the Science Achievement Test. Path analysis was employed as the statistical method, and a path diagram was used to illustrate the explanatory relationships among the observed variables. The analysis revealed that grade level positively and significantly predicts static and dynamic spatial reasoning skills, conceptual understanding of basic astronomy topics, and science achievement among gifted students. Additionally, both static and dynamic spatial reasoning skills positively and significantly predict students' conceptual understanding of basic astronomy topics. Similarly, science achievement is positively and significantly predicted by students' static and dynamic spatial reasoning skills as well as their conceptual understanding of basic astronomy topics. Overall, the findings indicate positive and significant direct and indirect relationships between gifted students' grade level, static and dynamic spatial reasoning skills, conceptual understanding of basic astronomy topics, and science achievement.