CSSR

CSSR may refer to:
 * Czechoslovak Socialist Republic (Czech and Slovak: ČSSR), onetime name of Czechoslovakia
 * Climate Science Special Report, Volume 1 of the Fourth National Climate Assessment (NCA4) 2017/2018
 * Canadian Society for the Study of Religion
 * Canadian Society for the Study of Rhetoric
 * Center for the Study of Science and Religion, a center inside The Earth Institute at Columbia University
 * Congregatio Sanctissimi Redemptoris, Latin name of the Congregation of the Most Holy Redeemer, abbreviated to C.Ss.R
 * Council with Social Services Responsibilities, part of the UK Healthcare Commission
 * Centre for Social Studies and Reforms (CSSR), based in Cochin, Kerala, India
 * Call setup success rate, a term used in telecommunications denoting the percentage of the attempts to make a call which result in a connection to the dialed number
 * Conservative Site-specific recombination