A tattletale is someone who reports on others' minor misbehavior, usually to get them in trouble rather than to help or protect anyone. When a classmate runs to tell the teacher that you whispered during silent reading, or that someone took an extra cookie at snack time, that's tattling.

Tattletales often focus on small rule-breaking that doesn't really hurt anyone. There's an important difference between tattling and telling an adult about something serious: if someone is being bullied, getting hurt, or doing something dangerous, speaking up isn't tattling. It's being responsible. But if you're reporting every tiny mistake just to see someone get in trouble or to make yourself look good, you're being a tattletale.

Many people dislike tattling about small things because constant reporting can break trust between friends and classmates. The word tattletale itself sounds childish and a bit silly, which matches how petty the behavior seems. Sometimes younger siblings become tattletales, running to parents about every small thing their older brother or sister does.

Other words for tattletale include snitch, informer, or telltale.