Temporal models associated with a multimedia presentation describe the ordering of presentation of various objects in the time domain. In multimedia presentations, this ordering of presentation is explicitly formulated and stored along with the multimedia objects. Temporal models specify parameters such as time instant, duration, and synchronization of an object presentation with those of others. The above parameters can be specified either in a hard or a exible manner. In the case of hard temporal specification, the parameters such as time instants and durations of presentation of objects are fixed. In the case of exible specification, these parameters are allowed to vary within a specified range. In this chapter, we present both hard and exible temporal models for multimedia presentations. We describe how these models can be used for understanding the resource requirements (in terms of disk bandwidth, buffers, and network bandwidth) of a multimedia presentation. We present some approaches for deriving retrieval schedules based on temporal models.