Experiences and constructions of menarche and menstruation are shaped by the sociocultural environment in which women are embedded. We explored experiences and constructions of menarche and menstruation among migrant and refugee women resettled in Sydney, Australia, and Vancouver, Canada. Seventy-eight semistructured individual interviews and 15 focus groups comprised of 82 participants were undertaken with women from Afghanistan, Iraq, Somalia, South Sudan, Sudan, Sri Lanka, and varying South American countries. We analyzed the data using thematic decomposition, identifying the overall theme "cycles of shame" and two core themes. In "becoming a woman," participants constructed menarche as a marker of womanhood, closely linked to marriage and childbearing. In "the unspeakable," women conveyed negative constructions of menstruation, positioning it as shameful, something to be concealed, and polluting. Identifying migrant and refugee women’s experiences and constructions of menarche and menstruation is essential for culturally safe medical practice, health promotion, and health education.