Industry practice shows that many of the problems in product design arise from a misunderstanding of the requirements or from the existence of ambiguities in the statement of the product requirements or from both. There has been a lack of a robust requirements management system to help designers to get the right requirements in the right time. The main objective of this thesis is to develop ontology for systematic gathering of product requirements.  The starting point of this thesis is the environment-based design theory by Zeng (Zeng, 2004), where product requirements are attributed to the conflicts in product environment. This present thesis extends the environment-based design theory in two aspects: first, ontology is developed for product environments based on product life cycle; secondly, ontology for product-environment relations is investigated from the perspective of traditional engineering sciences. By using these two sets of ontology, product requirements are classified into three levels: product, corporate, and environment. Based on the ontology and taxonomy developed in this thesis, systematic procedures are proposed to gather product requirements. A case study is used to demonstrate how this research can be applied to develop right product requirements for the product design.