Derry Girls features a main character, Clare Devlin, who comes out as lesbian. Her journey is depicted with humor and sensitivity, and her friends ultimately offer acceptance and support. The show portrays her with dignity and complexity, affirming her identity within the narrative without reducing her to a stereotype or making her sexuality solely a source of conflict.

The series uses satire to explore the cultural and institutional aspects of Catholicism in Northern Ireland, particularly through a Catholic girls' school. While humorously critiquing strict religious education and the absurdity of sectarianism, the narrative ultimately portrays the Catholic community with warmth and nuance. It also actively works to humanize Protestants, positioning the audience to critique bigotry and conflict that misuse religious identity, rather than condemning the faiths themselves.