The purpose of this research was to develop a "Crabs in a Bucket at Schools Scale" (CBSS) measuring the perceptions of teachers regarding crab mentality in educational organizations. The data of the study was collected in 2019-2020 academic year from high school teachers working at different high schools of Aydin province, located in Aegean Region in Turkey. In order to provide the validity of the measurement tool, content and construct validity analyses were performed. So as to provide content validity, the item pool was subjected to expert view and expert panel. Following this, the data was collected from high school teachers by using the 44-item draft scale and then, the data was subjected to construct validity analysis. For construct validity, Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA) were performed by using separate datasets (305 participants for EFA and 279 participants for CFA). In an effort to provide the reliability of the scale; Cronbach Alpha, Spearman-Brown and Guttman Split-Half coefficients were calculated. As a result of the analyses, it was concluded that the scale comprised a 27-item and 2 factor ("individual factors sub-dimension" and "organizational factors sub-dimension") structure, and the psychometric properties of CBSS was quite valid and reliable. [This study is part of the doctoral dissertation written by the corresponding author and it was presented as an abstract paper in International Pegem Conference on Education (IPCEDU) held in Turkey between September 16-19, 2020.]