Mrs. Plank is the 2nd grade teacher of Lily Tucker-Pritchett.
She appears in "Won't You Be Our Neighbor" where Mitchell and Cameron think she's putting pressure on Lily and she also gives homework on weekends. Mitchell and Cameron are displeased by this and they find out that there is an opening in Ms. Sparrow's class and they want for Lily to take it, since they believe that Lily is stressed out by Mrs Plank. Ms. Sparrow's class is more fun and kids are happy there. Without asking Lily, they meet Mrs Plank and they manage to move Lily to Mrs Sparrow's class but they soon find out that Lily does not want to change teacher because she loves Mrs Plank and she actually learns new and important things there. Cameron and Mitchell are forced to go back to Mrs Plank and beg her to take Lily back.