Parallel play is a form of play where children play adjacent to each other, but do not try to influence one another's behaviour. Children usually play alone during parallel play but are interested in what other children are doing. This usually occurs after the first birthday.  It usually involves two or more children in the same room that are interested in the same toy, each seeing the toy as their own. The children do not play together, but alongside each other simply because they are in the same room. Parallel play is usually first observed in children aged 2-3. An observer will notice that the children occasionally see what the others are doing and then modify their play accordingly. The older the children are, the less frequently they engage in this type of play. However, even older preschool children engage in parallel play, an enduring and frequent activity over the preschool years. Additionally, it is sometimes observed in older children when playing video games, particularly hand-held games. In education, parallel play also describes activities where students are divided into pairs or small groups and work on the same activity simultaneously. This gives all students equal opportunity for active involvement and reduces exposure - since all students are playing, none are watching.
Mildred Parten was one of the first to study peer sociability among 2 to 5-year-olds in 1932. Parten noticed a dramatic rise of interactive play with age and concluded that social development includes three stages. Parallel play is the first of three stages of play observed in young children. The other two stages include simple social play (playing and sharing together), and finally cooperative play (different complementary roles; shared purpose). Research indicates that these forms of play emerge in the order suggested by Parten, but they do not form a developmental sequence in which later-appearing ones replace earlier ones. All types coexist during the preschool years.
Developing skills 
Parallel play helps children begin language development and create social relationships. It can also assist with gross and fine motor skills, through the child's own individualized play. Parallel play can increase confidence because children are learning to play near others. Children can observe one another and learn to use new skills from playing alongside others. Eventually, it will lead to social development where the child will form relationships with others during play. Parallel play can be useful in encouraging expression of a child's feelings through their own individualized play. The child will increasingly learn to share and become aware of others emotions, as well as learn cause and effect through trial and error of adjusting and solving problems in play.
- Kail, R.V., & Cavaunaugh, J.C. (2007) Human Development: A Life-Span View (5th ed.). Belmont, CA: Wadsworth, Cengage Learning.
- Santrock, John (1999.). Life-Span Development. New York: McGraw Hill, Inc. ISBN 0-697-36439-9.
- Vasta, Ross (1999). Child Psychology. New York: John Wiley & Sons, Inc. ISBN 047119221 Check
- Berk, Laura (2004). Development of the Life-Span. Boston: Allyn & Bacon. ISBN 0-205-39157-5.