The chapter provides a comprehensive overview of the Harappan Civilisation, also referred to as the Indus Valley Civilisation. It traces the study of this civilisation back to Charles Masson's visit in 1826 and John Marshall's formal announcement in 1924. The chapter includes numerous discoveries from Harappa and Mohenjo-daro, highlighting typical Harappan artefacts that facilitated its identification. Dating to the third millennium BCE, this civilisation is recognised for its sophisticated urban planning and extensive trade networks, as well as cultural connections with Mesopotamia. These contacts were identified as early as 1924 following the discovery of Harappan artefacts within datable contexts at various sites in modern-day Iraq. The chapter summarises key discoveries that enhance our understanding of the civilisation. It discusses the geographical distribution of Harappan sites across the Indus and Sarasvati (Ghaggar-Hakra) river systems, known as the Greater Indus Region, and examines the significance of the “lost” Sarasvati River in settlement patterns. Numerous settlements were located along the Sarasvati River during the Harappan phase, later shifting upstream after the river dried up, indicating reliance on the river during the urban phase. Additionally, the text emphasises the usage of various terminologies and advocates for adopting standardised terminology. The chronology detailed includes phases from the Early Harappan (~3200–2600 BCE) to the Harappan (~2600–1900 BCE) and Late Harappan (~1900–1400 BCE). The chapter analyses the impact of climatic conditions, particularly the 4.2 ka aridification event, on the civilisation's development and subsequent deurbanisation. Key excavations at sites such as Mohenjo-daro, Harappa, and Dholavira have significantly advanced our understanding of Harappan culture.