Incorporating sustainability principles into university and college course offerings is pivotal in molding future leaders and innovators. This study focuses on the Philippines, where higher education institutions (HEIs) increasingly embed sustainability into their academic and operational frameworks. This study aims to quantitatively assess the level of teacher intention to integrate sustainability into curricula in higher education. Utilizing the expanded Theory of Planned Behavior (TPB), it examines the relationships between sustainability knowledge, concern for sustainability, perceived behavioral control, subjective norms, attitude towards sustainability integration, and the intention to integrate sustainability. The methodology involves a cross-sectional study using a web-based survey disseminated through multiple platforms. The sample size was determined through a priori calculation and proportional stratified sampling, with 227 respondents. Utilizing Structural Equation Modeling (SEM) and the Theory of Planned Behavior (TPB), this study uncovers that educators’ attitudes notably shape intentions to integrate sustainability into curricula. While the direct effect of perceived behavioral control is limited, institutional support is deemed to be crucial. Additionally, sustainability concerns strongly influence educators’ intentions, emphasizing the necessity for environmental awareness. These findings inform policymaking and underscore the significance of fostering sustainable practices in higher education through institutional support and awareness initiatives. Finally, this study aims to enhance the effectiveness of sustainability education in the Philippines and contribute to global sustainability efforts.