This thesis examines Māori cosmological stories, ceremonies, and traditional practices regarding menstruation in pre-colonial Māori society. I use kaupapa Māori and mana wahine as a theoretical and methodological framework, contextualising these stories within Māori cultural paradigms.This is important because menstruation has been framed within deeply misogynist, colonial ideologies in some ethnographic accounts, distorting menstrual rites and practices beyond recognition. These interpretations have been used to inform colonialist narratives of female inferiority in traditional Māori society, attempting to change Native constructs of womanhood. Such narratives have been perpetuated in contemporary literature, reinforcing powerful discourses of menstrual pollution and female inferiority. This thesis is a challenge to such representations. By examining menstrual stories located in Māori cosmologies, and investigating tribal histories, oral literatures, ceremonies and rites, I argue that menstruation was seen as a medium of whakapapa (genealogy) that connected Māori women to our pantheon of atua (supernatural beings). A study of ancient menstrual rites, recorded in tribal songs and chants, reveal that menstrual blood was used for psychic and spiritual protection. These examples unveil striking Indigenous constructs of womanhood that transform colonialist interpretations and radically challenge notions of female inferiority and menstrual pollution. I maintain in this thesis that presenting menstruation and menstrual blood as putrid is a politically motivated act of colonial violence that specifically targets the source of our continuity as Indigenous People, the whare tangata (house of humanity – womb of women). I pose the question ‘if menstrual blood symbolises whakapapa, what does it mean to present it as ‘unclean’ and how do such representations cut across the politics of tino rangatiratanga (autonomy)?’ Through in-depth semi-structured interviews, kōrero (dialogue), and wānanga (series of conversations) with Māori women, including cultural experts, scholars, artists, and mana wahine exponents, I gather a collection of ceremonies, stories, and wisdoms that reclaim Māori spiritualities which celebrate menstruation as divine. Within the context of a colonial history of marginalisation, this work is an activist site of political resistance which takes a step towards re-threading the feminine strands in the spiritual fabric of our world, torn asunder by the ideological imposition of a colonial, Christian male god. I argue, that menstruation is a potent site of decolonisation, cultural reclamation, and resistance toward the perpetuation of colonial hegemony.