The discovery of the Harappan Civilization in the greater Indus Valley has been significant issue of discussion, as well as the causes of its downfall in the mid second millennium B.C. This work investigates all the major factors suggested to have contributed to the end of the Harappan Civilization and also considers whether it declined or collapsed. I have elaborated the causes of the decline of Harappan civilization with special reference to Dholavira in these five chapters. However, I have mentioned all the factors which were responsible for the decline. The objective of the study is to explore the various possible causes that might have been responsible for the decline of Harrapan civilization and Dholavira in particular.This work is very much useful as the base to the academic researchers or anyone else who may be interested in history & architecture of early civilizations, on the decline of Harappan civilization and mainly with reference of its towns, particularly Dholavira in Gujarat, India.