Chlamydia infection, often simply known as chlamydia, is a sexually transmitted infection caused by the bacterium Chlamydia trachomatis. Most people who are infected have no symptoms.

When symptoms do develop this can take a few weeks following infection to occur.

Chlamydia is one of the most common sexually transmitted infections (STIs).

Chlamydia does not spread through casual contact such as shaking hands or using the same toilet as someone who is infected.