The optimal time to enter emerging industries is a key concern in strategy, yet scholars struggle to create a theoretical foundation that can integrate conflicting empirical findings. We incorporate categorical dynamics to industry life cycle theory to enhance existing entry timing theories. We introduce the concept of a dominant category�the conceptual schema that most stakeholders adhere to when referring to products that address similar needs and compete for the same market space�linking it to the dominant technological design and entry-timing advantages. In particular, we propose the existence of a window of opportunity for firm entry that starts with the emergence of the dominant category and ends with the emergence of the dominant design