Business domain knowledge of business analysts plays an important role in acquisition of client requirements and communication of requirements to the team in information systems development (ISD) projects. While working as a business analyst, I came to know from other business analysts that they had difficulties in handling some projects due to lack of domain knowledge. These conversations stimulated my interest to conduct this study to better understand role of business analysts’ domain knowledge in acquisition and communication of requirements. The review of literature provided the theoretical foundation for my study by showing that business analysts’ domain knowledge is crucial to acquire client requirements and transforming those requirements into accurate requirements prescriptions. The literature also showed that business analysts’ domain knowledge helps them to communicate the requirements effectively to internal software teams and client stakeholders for a shared understanding of the problem domain. The study was conducted at Auckland, New Zealand and involved eliciting the perceptions of ten business analysts on the role of business domain knowledge in acquisition and communication of requirements. The participants’ responses were obtained through semi-structured interviews. A deductive approach was used in the thematic analysis of participants’ responses, duly utilising the theoretical foundation provided by the literature review. The thematic analysis resulted in the emergence of four themes - business domain knowledge, requirements acquisition, communication of requirements and domain knowledge vs soft skills - with their respective sub-themes. The main theoretical implications of the study is that business analysts should first gain sufficient business domain knowledge before the requirements acquisition process as the knowledge is crucial for them to gain the clients’ trust, clearly understand client’s needs and develop accurate requirements prescriptions documents. The study had also shown that business analysts should improve their domain knowledge for effective communication of requirements to the internal development team as well as to create a shared understanding of requirements by clients and developers. The practical implication of the study for business analysts is that they should on their own gain sufficient business domain knowledge, through all means, for example, by self-learning or approaching subject matter experts (SMEs). The implication for ISD organisations is that they should support business analysts to gain domain knowledge through training courses, providing SMEs, and establishing well-maintained knowledge repositories.