One prominent cognitive developmental theory proposed that concepts of objects as coherent, enduring, and stable are constructed as infants gain experience interacting with objects and observing the consequences of object-oriented actions. An alternative account of object knowledge in infancy is based on the assumption that infants possess innate core knowledge of objects with which they reason about observed events. Here, a perceptual account of development of object concepts is proposed. On the perceptual account, young infants’ perception of object unity and that of object persistence, two foundations of mature object concepts, are susceptible to perceptual constraints such that young infants require a combination of cues to perceive unity or persistence across occlusion. Young infants thus perceive object persistence only under limited conditions, and over the early months, perception of persistence becomes more robust. In the chapter, the authors argue that these perceptual developments within the first six postnatal months likely underpin the later development of cognitive principles, including object concepts, and present substantial empirical support for the perceptual account.