FXR may refer to:Biology
- Farnesoid X receptor, a nuclear receptor that in humans is encoded by the NR1H4 gene.
- FXR1, fragile X mental retardation syndrome-related protein 1, a protein that in humans is encoded by the FXR1 gene
- F. X. Reid, pseudonym of British computer science academic Mike W. Shields
- Franz Xaver Rudolf von Höhnel (1852–1920), Austrian bryologist, mycologist, and algologist
- Foxer or FXR, an acoustic decoy device used to confuse homing torpedoes in World War II
- FXR Super Glide II, part of the Harley-Davidson Super Glide motorcycle line