Baby rattles are simple toys designed to stimulate infant development through the senses of sight, sound and touch. Most baby rattles are constructed from wood, plastic, rubber or fabric and contain small pellets to generate a rattling sound. Manufacturers of baby rattles must be especially aware of potential choking hazards and sharp edges during the design phase. Parents usually place baby rattles near their babies and allow them to naturally interact with the toys.

Baby rattles are actually more than simple toys when it comes to child development. A newborn's vision is still underdeveloped for several months, which leads him or her to become more of an auditory learner. When infants encounter baby rattles for the first time, they may not even see the toys clearly. They begin to realize that a world outside of themselves does indeed exist, and they can interact with the rattle through the grasping instinct. Gripping baby rattles and creating familiar sounds gives very young infants the first notion of a subject-object world.

Another important stage in a infant's development is cause and effect. Baby rattles are designed to perform consistently. A child soon learns that there is a direct relationship between his or her actions and the desired results. If an infant were presented with baby rattles that didn't make a sound, he or she would become very confused and frustrated. Different baby rattles with different sounds, however, might stimulate a baby's natural sense of curiosity. This idea of different causes and effects leads directly to other early infancy toys such as mobiles and activity boards.

Many baby rattles are sold in conjunction with teething rings. Babies going through the painful process of teething may also use baby rattles to soothe their gums. Babies also tend to process information about an object by tasting it, so baby rattles must be kept as clean as possible. They should also be inspected for cracks and other damage. The materials used for rattling should not be toxic, but accidental ingestion could be a frightening experience.

Commercial baby rattles are generally discarded as the infant develops into a toddler. Toddlers may still enjoy toys which generate noise, but baby rattles as such may no longer hold their interest. Some parents or grandparents may create sturdier baby rattles called 'heirloom rattles' out of turned wood. These rattles may be stored for future generations or kept as a permanent memento of a child's first year of life.