The mixed 4 × 100 metres relay at the 2025 World Athletics Relays was held at the Tianhe Stadium in Guangzhou, China on 10 and 11 May.
It was the first time a mixed 4 × 100 metres was held at the World Athletics Relays.
Records.
No records were established prior to the championships.
Qualification.
On 10 November 2024, World Athletics announced the qualification system for the championships. The top 16 teams in each event at the 2024 Summer Olympic Games qualify for entry to the championships. The host country China will enter with one team in each event, regardless of any entry conditions. The remaining teams (up to 32 in total per event) will be determined through the top lists in the qualification period (1 January 2024 to 13 April 2025).
Results.
Heats.
The heats were held on 10 May 2025, starting at 19:01 (UTC+8) in the evening. Qualification: First 2 of each heat () plus 2 fastest times () qualify to the Final.
Final.
The final was held on 11 May 2025, starting at 19:05 (UTC+8) in the evening.