Teachers of a preschool classroom filled with three- and four-year-olds regularly post a set of rules for parents and children to read. These rules almost always include safety. Parents and teachers both want the children to stay safe during the time they spend at school. Other themes include etiquette, cleanliness and ethics. Communicating the rules to the parents and children is essential to their success. Teachers might discuss with the kids what is important before writing the rules out, or they may have the children actively participate in making flyers or books with the rules to pass out to their peers and parents.

Safety
Staying safe in school starts from the moment the first child walks through the door. Many rules of safety include the parents. Children generally must be signed in and signed out by a parent or guardian. The children may not be unattended at school. The doors are usually locked after a certain hour to keep them safe inside. Safety for the children themselves includes walking rather than running in the classroom to prevent slipping, and keeping their hands to themselves to prevent bumps and bruises caused by other children. Safety also includes teaching the children to tell the teacher immediately about any safety issues or hazards.

Etiquette
As future members of society, the three-year-olds learn about etiquette and their classroom includes etiquette rules. These include asking for things nicely, standing in line without pushing, and remembering to listen and follow directions. "Inside voices," and "outside voices," the appropriate tone of voice for indoors and outside playtime, are regularly included in the rules.

Cleanliness
Cleanliness is practiced all day at a preschool. The children have rules about wiping themselves after using the toilet and flushing the toilet. Rules include washing their hands after using the toilet, before meals and after getting messy outside. They also have rules about cleaning up after themselves after lunch and snack time, and some three-year-old classrooms have rules about cleaning and organizing the classroom.

Ethics
The age of three is a time when many children are learning the difference between right and wrong. Ethics rules almost always include the rights of a child's personal property. Children need to understand that someone else's item is not theirs to take without permission. This also includes the teachers' possessions and anything belonging to the school.