Linezolid (INN) ( ) is a synthetic antibiotic, the first of the oxazolidinone class, used for the treatment of infections caused by multi-resistant bacteria including streptococcus and methicillin-resistant Staphylococcus aureus (MRSA). It is marketed under the trade name Zyvox (or Zyvoxid in Europe) (Pfizer).

It was the first commercially available oxazolidinone antibiotic.

Compared to the older antibiotics it is quite expensive.