Co-sleeping is a practice in which babies and young children sleep close to one or both parents, as opposed to in a separate room. Co-sleeping individuals sleep in sensory proximity to one another, where the individual senses the presence of others. This sensory proximity can either be triggered by touch, smell, taste, or noise. Therefore, the individuals can be a few centimeters away or on the other side of the room and still have an effect on the other. It is standard practice in many parts of the world, and is practiced by a significant minority in countries where cribs are also used.

Bed-sharing, a practice in which babies and young children sleep in the same bed with one or both parents, is a subset of co-sleeping. Co-bedding refers to infants (typically twins or higher-order multiples) sharing the same bed.

The American Academy of Pediatrics does encourage room-sharing (sleeping in the same room but on separate surfaces) in its policy statement regarding SIDS prevention, but it recommends against bed-sharing with infants.

Recent legal rulings suggest that bed-sharing has been attributed as a factor of unintentional infant suffocation. For instance, parents under the influence of drugs or alcohol and whose children died while bed-sharing have been charged and, at times, prosecuted with manslaughter in several US states (including Minnesota, Michigan, Georgia, Pennsylvania, Texas, Wisconsin and Utah).