Time is a central concept but its nature and status in in Organization Studies remains under-studied. By opening the study of time on the sociomaterial perspective, we argue that construction of time is anchored in very heterogeneous human and non-human elements. Two main ideas are developed. The first one is that the definition of time is always performed within an entanglement of the human and non-human produces and reproduces over time. Also, the temporality and pace of activities are based on heterogeneous elements that permit the objectification of this temporality. Our second theoretical proposal addresses the status of time in activities. Whatever the ontology of time, actors perceive time as an external force influencing their daily life. Time is defined as a limited resource that both enables and constrains the activity. Furthermore, time can be comprehended as a non-human actor playing a role in the course of activities. We illustrate these theoretical proposals using a case about the development of a competencies management device in a bank. From this empirical illustration, we highlight several materializations of time within the project: some regarding the anticipation of the project, and other developing during the course of the project. Finally, we discuss the role and the status of time in activities, and thus, in Organization Studies. More precisely, we discuss the mediation role played by representations of time in organizing.