2023 World Athletics Championships – Women's 400 metres

The women's 400 metres at the 2023 World Athletics Championships was held at the National Athletics Centre in Budapest, Hungary from 20 to 23 August 2023. The winning margin was 0.81 seconds which as of 2024 is the only time the women's 400 metres has been won by more than 0.7 seconds at these championships.

Summary
The buildup to the event was very hectic, as world leader Sydney McLaughlin-Levrone withdrew just a few weeks before the championships started, citing a minor knee injury. 2019 champion and #3 all-time Salwa Eid Naser also withdrew, just days before the heats started. Aside from the withdrawals, some big names also failed to make it past the first round. Defending champion and #6 all-time Shaunae Miller-Uibo was not back in full form, as she returned to the track just four months after giving birth to her first child. Another big name that failed to make it to the semi-final round was world number three Britton Wilson, who finished last in her opening heat. All of the semi-finalists had sub-50 credentials, six of them broke 50 in the semi-final round. That also meant they all had a sub-50 recently.

In the final, Lieke Klaver was out fast, making up the stagger on Natalia Kaczmarek to her outside down the backstretch. After the halfway mark, returning silver medalist Marileidy Paulino began to make up ground on returning bronze medalist Sada Williams to her outside. When Paulino hit the 100 metre start line, she had a step on Klaver and two more on her next pursuers Williams, Rhasidat Adeleke and Kaczmarek. Down the stretch, Klaver was gritting her teeth but was moving backwards relative to Kaczmarek, Adeleke and Williams, but Paulino was so far this was clearly a battle just for silver. Kaczmarek emerged as the next best, holding a step on Williams as Adeleke faded. Paulino finished 6 metres up on Kaczmarek with Williams taking a second bronze in a row.

Paulino's 48.76 National Record makes her the eleventh fastest in history. Only the three medalists were able to break 50 in the final.

Records
Before the competition records were as follows:

Qualification standard
The standard to qualify automatically for entry was 51.00.

Schedule
The event schedule, in local time (UTC+2), was as follows:

Heats
The first 3 athletes in each heat (Q) and the next 6 fastest (q) qualify for the semi-finals.

Semi-finals
The first 2 athletes in each heat (Q) and the next 2 fastest (q) qualify for the final.

Final
The final was held on Wednesday 23 August 2023.