|Film Appearance?||Yes (Mentioned only)|
|Online Appearance?||Yes (as Mrs. Gretchen)|
|Book Appearance?||Yes (Mentioned only)|
Ms. Gillman is a woman from the PTA mentioned in Rodrick Rules and the online version. Greg's mother, Susan, doesn't appear to like her, as when Ms. Gillman called the Heffley-home, asking to speak to Susan, Susan told Greg (who was on an "honesty pledge" from Susan) told Greg to tell Ms. Gillman that she wasn't home. Greg, unsure of whether his mom was trying to trick him into lying or something, didn't want to break his honesty streak over something like this, so he made Susan go outside before telling Ms. Gillman that "[his mother] is not in the house at the moment," so that he would still technically be telling the truth.
After that happened, Susan didn't hold Greg to his honesty pledge anymore.