The main purpose of this article is to present a model for information-seeking behaviour with an emphasis on unplanned and planned behaviour of users in using library resources and services. The working method was that, reviewing the literature and previous information behaviour models, such as Wilson, Ellis, Kuhlthau, and Dervin models, this article proposes a novel model of information-seeking behaviour for library users. Our model of information-seeking behaviour was developed by combining the existing models of planned information-seeking behaviour with the focus on the factors affecting unplanned rather than planned behaviour of users in accessing resources or services. Our proposed model for information-seeking behaviour of clients has two main parts. The first part planned behaviour resulting from a problem or a certain information need according to which the user seeks to find information in a planned manner. The second part deals with unplanned behaviour shaped by a hidden or uncertain information need. Finally, both types of behaviour can result in the discovery, extraction, collection and use of information.