This study explores the engagement and efficacy of secondary school teachers concerning the sustainability of research culture, focusing on the moderated mediating effects of ancillary functions and research productivity. Utilizing a quantitative research design, data were collected through surveys from a sample of secondary school teachers. Engagement, efficacy, ancillary functions, research productivity, and sustainability of research culture were assessed and analyzed using regression and mediation analyses. The findings reveal high engagement and efficacy among secondary school teachers in various research-related activities, indicating a strong commitment to research endeavors within educational contexts. Ancillary functions, including administrative tasks and professional development, significantly influence teachers' engagement and productivity in research, contributing to the sustainability of research culture. Moreover, research productivity partially mediates the relationship between teachers' engagement/efficacy in research and the sustainability of research culture, highlighting the importance of fostering a productive research environment to sustain the research culture within educational institutions. The study's scope is limited to secondary school teachers and researchers from the Division of Quezon, which comprises the four congressional districts. Data collection took place between January and April 2024, preceding the conclusion of the 2023–2024 school year. The primary data were gathered using a survey instrument administered to all respondents. Future research could employ prospective studies and explore additional factors influencing the sustainability of research culture. This study contributes to the existing literature by examining the complex interplay between teacher engagement, efficacy, ancillary functions, research productivity, and the sustainability of research culture. Identifying ancillary functions as significant predictors and mediators enriches our understanding of the mechanisms underlying the sustainability of research culture within educational institutions, offering practical implications for policymakers, educators, and researchers aiming to promote research excellence in secondary schools.