किसी देश अथवा किसी भी क्षेत्र में लोगों के बारे में विधिवत रूप से सूचना प्राप्त करना एवं उसे रिकॉर्ड करना करना जनगणना (census) कहलाती है। यह एक निश्चित समान्तराल के बाद की जाती है और शासकीय आदेश के तहत की जाती है।

A census is the procedure of systematically acquiring, recording and calculating population information about the members of a given population. This term is used mostly in connection with national population and housing censuses; other common censuses include censuses of agriculture, traditional culture, business, supplies, and traffic censuses. The United Nations (UN) defines the essential features of population and housing censuses as "individual enumeration, universality within a defined territory, simultaneity and defined periodicity", and recommends that population censuses be taken at least every ten years. UN recommendations also cover census topics to be collected, official definitions, classifications and other useful information to co-ordinate international practices.