This study aimed at constructing a scale of implicit mathematical intelligence, which used for measuring students' beliefs related to mathematical intelligence in a valid and reliable way. The study followed the descriptive approach and the researcher used appropriate statistical methods to answer the questions of the study. The study sample consisted of 716 students, from three Omani governorates. The validity of the scale was checked by many ways which are face validity, factor analysis (using cross- sample validation), and concurrent validity (using criterion related validity and predictive validity). The results showed acceptable validity indices, and the results of the factor analysis showed two structure factors. The reliability of the scale was examined by using Cronbach's alpha, and test-retest method. The results indicated good scale reliability. Cronbach's alpha was (0.81) for the constant implicit mathematica] intelligence domain and (0.78) for the changing implicit mathematical intelligence domain. Besides, test-retest reliability index was (0.88) for the constant domain and (0.86) for the changing domain. In the light of the theoretical framework and previous studies, results were discussed and the study ended with a number of recommendations and suggestions.