Biodiesel is a promising renewable energy alternative as it is relatively cleaner, inherently biodegradable and less toxic than conventional diesel fuels. The present study evaluates the sustainability of biodiesel production by simultaneously considering technology selection: conventional reactor-distillation (CV) and reactive distillation (RD) processes, and catalyst selection: homogeneous (HM) and heterogeneous (HT) base catalysts. The main motivation of this work is the need to address a research gap in prior studies, which have generally examined technology and catalyst selections separately. The sustainability assessment in this study includes 11 indicators in the techno-environmental dimension and 4 indicators in the economic dimension. The results reveal a strong correlation between sustainability and unit operation performance. The life cycle assessment indicates that RD can reduce impacts on ecosystem quality and human health by up to 5.5 % compared to conventional processes. Notably, HT-RD and HT-CV take the two opposite extreme sides across most techno-environmental and economic dimensions, highlighting the significant influence of technology choice on overall sustainability when an identical catalyst is utilized. Therefore, this study emphasizes that technology evaluation should not be considered independently of catalyst selection when conducting a sustainability assessment. © 2025 Institution of Chemical Engineers