The women's 400 metres hurdles event at the 2009 European Athletics U23 Championships was held in Kaunas, Lithuania, at S. Dariaus ir S. Girėno stadionas (Darius and Girėnas Stadium) on 16, 17, and 18 July.
18 July
17 July
Qualified: first 3 in each heat and 2 best to the Final
16 July
Qualified: first 3 in each heat and 4 best to the Semifinal
According to an unofficial count, 27 athletes from 16 countries participated in the event.