2012 World Junior Championships in Athletics – Women's 4 × 400 metres relay

The women's 4 × 400 metres relay at the 2012 World Junior Championships in Athletics was held at the Estadi Olímpic Lluís Companys on 14 and 15 July 2012.

Records
, the existing world junior and championship records were as follows.

Heats
Qualification: First 3 of each heat (Q) plus the 2 fastest times (q) qualified

Participation
According to an unofficial count, 59 athletes from 13 countries participated in the event. • (5)

• (4)

• 🇨🇴 colombia (4)

• (5)

• 🇭🇺 hungary (4)

• 🇯🇲 jamaica (5)

• 🇰🇿 kazakhstan (4)

• 🇵🇱 poland (4)

• 🇷🇴 romania (4)

• (4)

• undefined (5)

• 🇺🇦 ukraine (5)

• (6)