SFR (French: [ɛsɛfɛʁ]; Société française du radiotéléphone, [sɔsjete fʁɑ̃sɛz dy ʁadjotelefɔn]) is a French telecommunications company It is the second oldest mobile network operator in France, after Orange and the second largest telecommunications company in France, behind Orange.

As of December 2015, it had 21.9 million customers in Metropolitan France for mobile services and provided 6.35 million households with high-speed internet access.

SFR also offers services in the overseas departments of France, in the Caribbean islands of Martinique, Guadeloupe, and in Guyane through SFR Caraïbe, as well as in the Indian Ocean, in Mayotte and the Réunion islands through SRR (Société Réunionnaise du Radiotéléphone), although the company is branded as SFR Réunion.

SFR (SFR Belux) operated in Belgium as a cable operator and MVNO in some communes of Brussels Region and in some areas of Luxembourg. The division was sold to rival Telenet (owned by Liberty Global) in December 2016.