Mrs. Myers is Jess and Leslie's fifth grade teacher. The first thing we hear about her is that she's super nice-acting on the first and last days of school – those are supposedly the only days she smiles – and the rest of the time she's really strict and hardcore. For the first portion of the book, it seems as though this is true. With her strictness and severity, Mrs. Myers comes off pretty poorly in comparison to Miss Edmunds. She favors Leslie a little because, let's face it, Leslie's a fantastic student who turns in work well above the quality of what the other students produce. But praise from Mrs. Myers just gets Leslie the wrong kind of attention.
Jess usually experiences Mrs. Myers as an eagle-eyed person who can tell when he's not paying attention and tries to keep him in line. He realizes she's more than that, though, when he returns to school after the tragedy and she calls him out into the hallway. He thinks she's going to chew him out and is judging her as mean and uncaring, but is in for a rude surprise when he sees that "Behind her turned up glasses, Mrs. Myers' narrow eyes were full of tears" (13.53). She says she wants to "offer him [her] sympathy" and explains how sad she was when her husband died. This humanizes her to Jess, who'd never thought about his teacher's personal life.
Maybe her grief about her husband explains her short temper or strictness with the other students; certainly she's one of the few people in Lark Creek who saw Leslie's value and potential, although not as deeply or in the same way as Jess did. Of all the adults who interact with Jess after Leslie's death, his teacher is one of the ones who helps him the most: "Mrs. Myers had helped him already by understanding that he would never forget Leslie" (13.57). Although Jess didn't like Mrs. Myers very much, and enjoyed it when Leslie made fun of her, he was wrong to judge her so harshly. She's really a good person, who cared for Leslie and who cares for him.