An assessment of a good number of archaeological datasets available so far on small-grained millets from core (Upper Indus) and peripheral regions of the Indus/Harappan civilization is made to understand their role in the ancient crop economy and their diversity and spatial extent in relation to cultural change. Among the millets, sorghum millet from the Early Harappan level (3000–2500 BC) at Kunal (3%) and Banawali (3%), Mature Harappan level (2500–2000 BC) at Banawali (3%) & Rohira (20%) and Late Harappan level (2000–1400 BC) at Mahorana (6%), Hulas (5%), Sanghol (2%) and Pirak (1%), little millet from the Early Harappan (3300–2600 BC; 3.5%), Mature Harappan (2600–1900 BC; 4%) and Late Harappan (1900–1700 BC; 12.5%) levels at Harappa and finger millet (2%) and Italian millet (2%) from the Late Harappan (2000–1200 BC) level at Hulas and Sanghol respectively have been recorded in the core region (Upper Indus). The peripheral region of Harappan civilization shows the dominance of finger millet during the Mature Harappan (2500–2000 BC) at Rojdi (68%) and the Late Harappan (2000–1800 BC) level at Oriyo Timbo (40%), sorghum (22%) and pearl millet (36%) during the Late Harappan (2100–1700 BC) at Kanmer; Italian millet during Late Harappan (2000–1700 BC) at Rojdi (41%), Oriyo Timbo (23%) and Babar Kot (95%), along with little millet (5–19%) and foxtail millet (17–47%). The present dataset suspects their wider role in the Harappan agricultural system as a whole although they were present since the Early Harappan. The shift towards drought-resistant crops in peripheral region is to be inferred as cultural adaptation in response to decline of SW monsoon during the late Holocene (∼4 ka), to which millets are better suited.