["Business Strategy and the Environment, Volume 35, Issue 3, Page 3607-3624, March 2026. ", "\nABSTRACT\nA concerning surge in ecological challenges has heightened attention to the sustainability efforts related to stakeholders' expectations; however, the response of lean production, sustainable supply chain management (SSCM), and sustainable process innovation to these demands remains underexplored. Anchored by resource‐based view (RBV) theory, this paper undertakes a novel investigation and addresses the underexplored collective effects of lean production and SSCM on sustainability performance, covering the triple bottom line (TBL) dimensions while considering the moderating role of sustainable process innovation. Data were collected through a structured survey of 187 auto‐parts manufacturers affiliated with the Thai Auto Part Manufacturers Association (TAPMA). The hypotheses were tested using partial least squares structural equation modeling (PLS‐SEM). The findings reveal that lean production and SSCM are positively correlated with sustainability performance across all three dimensions of the TBL. Moreover, sustainable process innovation positively moderates the relationship between SSCM and both environmental and social performance, underscoring its pivotal role in amplifying sustainability outcomes. In contrast, the moderating role of sustainable process innovation in the SSCM and economic performance, does not follow sustainability‐oriented process innovations. Our research carries substantial implications, enriching the theoretical comprehension through empirically validating an integrated mechanism underlying lean production, SSCM, and sustainable process innovation to sustainability performance.\n"]