Teachers are the frontline workers in sustaining quality education; hence, assessing their knowledge, attitudes, and behaviors (KAB) allows them and the administrators to create better training, programs, and instructional materials. The objective is to develop and validate a quick and accessible online instrument to assess the teachers’ KAB towards sustainable development in the Philippine context, as part of a bigger project to integrate Pili (Canarium ovatum) into education. The researchers administered the instrument using a cross-sectional survey method through Google Forms in which respondents (n = 206) had voluntarily answered. The 24-item tool, anchored on the 2030 sustainable development goals and their complex systems, is reliable and valid based on the confirmatory factor analysis, and Cronbach’s alpha and Fleiss’s kappa estimates. The results showed that having favorable knowledge and attitudes toward sustainable development is inadequate to create positive behaviors. The adaptation of the developed instrument, the use of findings for intercultural and cross-cultural studies, and further investigations are recommended.