From Muppet Wiki

Mouse school is a fun place to learn for Tutter and his classmates, including Keisha, Luke, Lily, and Moss. Learning and other activities are overseen by Miss Maxwell. It's a one-room schoolhouse, but there's plenty of places to play and an occasional field trip.

Tutter first begins attending Mouse School in the fourth season of the program. He joins the school soccer team, coached by Bear, but considers quiting in "Show Your Stuff." In "Teacher Appreciation Day," Tutter joins with Lily to figure out a way to show Miss Maxwell how much the mice kids all appreciate her. Tutter holds a sleepover for his Mouse School classmates in "Tutter's First Big Sleepover Bash."