Older siblings have a great deal of influence on their younger siblings. In many cases, they assist their brothers and sisters in all aspects of motor development. The outcomes of younger siblings’ motor skill development, when interacting with older siblings in locomotor and object control activities, are key to promoting movement patterns. In addition, research found that older siblings have positive effects on their younger siblings, helping them reach proficiency in motor skills. However, other studies have shown that the influence of older siblings is not always beneficial. Therefore, the purpose of this paper was to review the effects of older siblings on motor skills including fundamental motor skills (FMS) of their younger siblings and to highlight the positive and negative aspects of older siblings’ influence on infants and young children. The findings of this paper suggest that age, imitation, and siblings of the same gender are positive aspects of siblings’ motor skill development. In addition, negative effects of siblings, such as fighting and arguing, were found. This paper can provide a better understanding of how to approach different methods of raising infants and young children to maximize the development of their motor skills including FMS.