Chlamydia is a sexually transmitted infection caused by the bacterium Chlamydia trachomatis.
Chlamydia may also refer to:
- Chlamydia (genus), a genus of pathogenic bacteria
- Chlamydia abortus, a chlamydial species that causes abortion in mammals
- Chlamydia caviae, a chlamydial species found in Guinea pigs
- Chlamydia felis, a chlamydial species found in cats
- Chlamydia muridarum, causing disease in mice and hamsters (the Muridae)
- Chlamydia pecorum, a chlamydial species common in livestock
- Chlamydia pneumoniae, also known as Chlamydophila pneumoniae, an airborne chlamydial species responsible for human respiratory infection and numerous animal infections
- Chlamydia psittaci, causes parrot fever
- Chlamydia suis, infects pigs (Sus scrofa)
- Chlamydia trachomatis, causing human sexually transmitted disease and eye infections