Inquiry learning is a powerful strategy to instill scientific thinking into the student. Therefore, it was aimed to develop a scale of inquiry learning skills towards geometry in this study. The study was designed according to a scanning model. The study group was determined according to the convenience sampling method. 514 middle school students participated in the study. The data obtained from these students were randomly divided into two groups, and exploratory and confirmatory factor analyses were performed. As a result of exploratory factor analysis, a structure consisting of 12 items and two sub-factors was revealed. This structure was tested by confirmatory factor analysis and the X[superscript 2] /df ratio of the scale was obtained as 2.13. This value proved that the scale fits perfectly. By performing item analyses, it was concluded that all items in the scale are highly distinctive. Reliability analyses were performed and it was detected that the scale was highly reliable. Using this scale, researchers could reveal students' level of inquiry skills towards geometry, reveal factors affecting students' inquiry learning skills based on geometry. Teachers could determine students' inquiry skills to learn geometry topics, and could decide what measures they can take in case of deficiency. [This study was presented as an abstract paper at the VII International Eurasian Educational Research Congress (EJER 2020).]