Integrated STEM education (iSTEMe) is increasingly emphasized in educational reforms around the world. These reformsprompted curricular changes in many countries, including Spain. In the Autonomous Community of Valencia, a new curriculummodel was introduced that organized both STEM and non-STEM subjects into broader interdisciplinary domains, designed to betaught through an integrated approach. However, the success of such reforms largely depends on teachers, who are the primaryagents of educational change. This underscores the importance of understanding their motivation and intention to implementiSTEMe. Drawing on the expectancy-value-cost model, this study examined secondary education teachers' motivations towardiSTEMe, with a particular focus on STEM teachers, who comprised 70.2% of the total sample (N = 439). The research addressedfour key questions: RQ1. What are secondary school teachers' expectancies for success, values, perceived costs, and intentions toimplement iSTEMe?; RQ2. How do secondary school teachers' expectancies for success, values, perceived costs, and intentionsto implement iSTEMe vary according to sociodemographic characteristics?; RQ3. To what extent are secondary school teachers'expectancies for success, values, and perceived costs related to their intentions to implement iSTEMe?; and RQ4. To what extentdo sociodemographic characteristics mediate the relationship between teachers' expectancies for success, values, and costs andtheir intention to implement iSTEMe? Multivariate analysis and Partial Least Squares Structural Equation Modeling revealedthat teachers generally feel unprepared to implement iSTEMe, perceive limited pedagogical value in it, and associate it with sig-nificant instructional and learning challenges. Consequently, their intention to adopt iSTEMe was low, and this was associatedwith the perceived lack of pedagogical value. These findings raise concerns about the feasibility of iSTEMe reforms, which maystruggle to succeed without stronger support and greater teacher engagement.
