Entecavir (INN) (pronounced /ɛnˈtɛkəvɪr/) is an oral antiviral drug used in the treatment of hepatitis B infection. It is marketed under the trade name Baraclude (BMS).

Entecavir is a nucleoside analog (more specifically, a guanine analogue) that inhibits reverse transcription, DNA replication and transcription in the viral replication process. The drug’s manufacturer claims that entecavir is more efficacious than previous agents used to treat hepatitis B (lamivudine and adefovir).

Entecavir was approved by the U.S.FDA in March 2005.