Kantar Sifo, previously TNS Sifo and Sifo Research International, is a Swedish company operating in the field of opinion and social research.
Since 1967, Sifo has published its public opinion poll "Voter monitor" (Swedish: Väljarbarometern) which analyses the party allegiances of Swedish voters. Sifo is also known for one of the largest media surveys in the world – ORVESTO Konsument, for which almost 50 thousand people (out of total of 9 million citizens) are interviewed every year about their media and consumption patterns.
Kantar Sifo has its headquarters in Stockholm.