The concepts of extremism and fundamentalism are most thoroughly explored through the character of Miss Doris Kilman. Miss Kilman is presented as a poor, unattractive woman who is a devout Christian and tutors Elizabeth Dalloway. Miss Kilman has a zealous, extreme faith, and this fundamentalist approach to religion comes out in Miss Kilman's hatred of Clarissa Dalloway's wealth and privilege. Woolf presents Miss Kilman's hatred of Clarissa's privilege as a religious distaste for materialism, as Miss Kilman haughtily considers Clarissa's life to have been frittered away on earthly goods (125), while she is sometimes presented in the book as more of "a soul" than an actual woman (134).

However, if Miss Kilman's extreme religious views are unfair and mean-spirited, it is difficult to altogether dislike her. While Clarissa has had the benefit of wealth and good looks, Miss Kilman has had to struggle to work and support herself, and even recognizes herself as ugly and unpleasant. Thus, Miss Kilman's extremist views on religion and judgmental hatred of Clarissa are actually forms of jealousy: a working-class protest against a privileged woman. So, after we learn more about Miss Kilman's troubled and trying life, it is hard to avoid sympathizing with her, even if she uses religious extremism as a means of expressing her jealousy.