The appropriateness of young children's playful aggression within early childhood settings continues to be debated among early childhood professionals. Research suggests that children's play--all types of play--should be the foundation of early childhood practice; however, playful aggression continues to be a neglected aspect of early childhood curricula. While decades of research identify the significant developmental benefits within multiple domains of learning as derived from various aspects of play, strict policies prohibiting playful aggression remain. With a growing number of young children enrolled in preschool programs it is important for educators to provide beneficial and inclusive experiences conducive to fostering optimal development of young children in all learning domains. This article suggests that the intolerance of children's playful aggression may reduce their optimal development; more specifically, their cognitive, social, physical and communicative development may be limited or hindered due to the omission and/or exclusion of playfully aggressive opportunities. (author abstract)