["Business Strategy and the Environment, EarlyView. ", "\nABSTRACT\nThis study investigates the combined effect of top management environmental concern and eco‐product development effectiveness on firms' environmental performance. The study also considers the moderating impact of environmental information sharing on this process. Building on the integration of upper echelons perspective and resource‐based theory, the research model was tested using covariance‐based structural equation modelling with survey data from 171 small and medium‐sized technology firms operating in Nigeria. The findings show that top management environmental concern facilitates eco‐product development effectiveness, which in turn positively influences firms' environmental performance. Additionally, the findings indicate that environmental information sharing strengthens top management environmental concern but weakens the impact of eco‐product development effectiveness on environmental performance. These results contribute to extant literature by unpacking the boundary conditions through which the interplay of top management environmental concern and eco‐product development effectiveness can promote environmental performance within emerging market firms. For practitioners, the study generates valuable insights into how environmental information sharing can amplify or attenuate their environmental initiatives and performance outcomes.\n"]