This article describes the development, initial validation, and psychometric evaluation of the mathematical modeling attitude scale (MMAS). Specifically, both qualitative and quantitative techniques were used to generate relevant items. The MMAS assesses K-12 teachers' attitude toward mathematical modeling and examines their experiences with modeling practices. The initial scale development process included the results of items generated from relevant literature, expert reviews, and cognitive interviews to create and assess content validity of MMAS Items. The pilot study phase describes the results of psychometric properties and exploratory factor analysis conducted to assess the usefulness and reliability of the MMAS items measuring teachers' attitude toward modeling. The scale development process isolated four factors: "constructivism," "understanding," "relevance and real life," and "motivation and interest." These four factors explained about 70.2% of the variation in the 28-item measure. The Cronbach's coefficients alpha for the four factors ranged between 0.81 and 0.95, with an overall scale coefficient of 0.96. The findings presented provide evidence to support the scale's reliability and potential utility for measuring aspects related to teachers' attitude toward mathematical modeling. Additional results indicated that teachers had limited experience with modeling practices. Discussion, limitations, and implications for teacher education and future research are presented.