This study investigates whether board interlocks facilitate the diffusion of climate change exposure across firms. We use firm-level climate change exposure data developed by Sautner et al. (2023), which is derived from the relative frequency of climate-related terms in earnings conference call transcripts. Building on social network theory and resource dependence theory, we argue that shared directors act as important information carriers, allowing climate-related knowledge and awareness to flow between interconnected firms. Using a global sample of 62,290 listed firms from 2002 to 2024, we examine climate change exposure at the level of focal–interlocked firm pairs. Interlocked firms are identified based on shared board members. Our results show that the climate change exposure of interlocked firms is positively associated with the focal firm’s climate change exposure. Although the presence of an interlock relationship alone exhibits a negative association, its interaction with interlocked firms’ climate change exposure significantly strengthens the diffusion effect. We further demonstrate that interlock age plays a moderating role, with longer-standing interlock ties enhancing the transmission of climate change exposure from interlocked firms to focal firms. This suggests that sustained director relationships improve the credibility and effectiveness of climate-related information transfer.