In guidance for nurseries in England, the Department for Children, Schools and Families says staff should resist a "natural instinct" to stop such play. It says role playing helps create the right conditions for boys' learning and could help them become more engaged in education in the future.
Teachers have condemned the advice, saying toy guns "symbolise aggression".
The guidance - entitled Confident, Capable and Creative: Supporting Boys' Achievements - says "practitioners" often find boys' chosen type of play "more difficult to understand and value than that of girls".
Boys regularly use "images and ideas gleaned from the media" as starting points in play, the advice says, which "may involve characters with special powers or weapons".
"Adults can find this type of play particularly challenging and have a natural instinct to stop it," the guidance continues.
"This is not necessary as long as practitioners help the boys to understand and respect the rights of other children and to take responsibility for the resources and environment."
