The airport handled more than 107,000 passengers on 27 October.
The new daily record beat the previous high of 104,000 set on 23 August.
In fact, it is the fourth time the record has been broken in 2024.
Strong demand for family holidays and short breaks, particularly during half-term, also saw Stansted record its busiest ever October with 2.67 million passengers using the airport.
That is an increase of 97,000 on last year.
Destinations in Turkey, the Canaries, Spain, and Portugal were the most popular for those heading away on holiday.
The number of passengers flying into Stansted over the period reached new heights as overseas visitors continued to use Stansted as their gateway to London and the East of England.
Operational performance during the month remained strong, with 99% of passengers passing safely through security in 15 minutes or less.
There was an average queue time of two minutes during the main departure peaks.
The number of passengers using London Stansted in the 12-months to the end of October stands at 29.45 million, an increase of 6.7% on the previous year.
Gareth Powell, London Stansted’s MD, said: “To record the busiest day in the history of London Stansted in late October is an incredible achievement and a powerful reflection of reliability, and operational efficiency the airport and our airline partners are able to offer.”