Abstract. Geology is colonial. It has a colonial past, and a colonial present. The majority of the knowledge we accept as the modern discipline of geology was founded during the height of the early modern European Empires colonial expansion. Knowledge is not neutral and its creation and use can be damaging to individuals and peoples. The concept of knowledge being colonial or colonised has gathered attention recently, but this concept can be misunderstood or difficult to engage with by individuals who are not familiar or trained to work with the literature on the issue. This paper aims to demystify Decolonising the Curriculum, particularly with respect to geology. We explain what Decolonising the Curriculum is, and outline frameworks and terminology often found in decolonising literature. We discuss how geology is based on colonised knowledge and what effects this may have. We explore how we might decolonise the subject and most importantly, why it matters. Together, through collaborative networks, we need to decolonise geology to ensure our discipline is inclusive, accessible to all and relevant to the grand challenges facing our civilization.