Cetti's Warbler, Cettia cetti, is a species of passerine bird in the warbler family found in wetland and river and lake ecosystems. It is a widespread breeder across much of southern Europe. This species favours swampy lowland areas with thick cover of reeds and sparse bushes (rarely in uniform reedbeds standing in water), willows (Salix), and brambles (Rubus) or blackthorn (Prunus spinosa). It is also found in overgrown ditches and streams with thick tangles of cover, areas of damp meadows, tall grass stands, hedgerows and overgrown orchards (European Red List 2015).

Cettia cetti has a breeding population size of 1760000-2620000 pairs and a breeding range size of 1250000 square kilometres in the EU27. The breeding population trend in the EU27 is Stable in the short term and Stable in the long term.

The EU population status of Cettia cetti was assessed as Secure, because the species does not meet any of the IUCN Red List criteria for threatened or Near Threatened, or the criteria for Depleted or Declining (the EU27 population or range has not declined by 20% or more since 1980).