Mrs. Douglas is a 5th-grade teacher at Derry School and is Ben Hanscom, Bill Denbrough, Beverly Marsh, Henry Bowers and Patrick Hockstetter’s teacher. Like most of the adult residents of Derry, she is somewhat aware of Derry's past and that there is something wrong with the town but refuses to talk about it and also has forgotten about It, therefore not believing in it.
She is also aware that Patrick Hockstetter is disturbed, if not aware he is a psychopath, and attempts to keeps him away from the female students, though she is relieved he is a quiet nuisance, unlike the rest of the Bowers Gang. Ben also has a mild crush on her which develops after he helps her out one January afternoon.
She appears in the 1990 miniseries, who appears to be a kind, caring woman who doesn’t like Henry Bowers and often criticises his behaviour, disciplining it at times, at one time giving Henry detention for one hour after school every day of the week. She does not appear in the 2017 adaptation nor its sequel.