There are a total of 4,726 people cramming into every square kilometre of the capital. That's compared to an average of 257 people per square kilometre across the country as a whole.
Space management software company, CloudBooking, analysed data from the University of the West of England to produce the figures.
However, the UK capital's overcrowding problem pales in comparison with the world's most cramped cities.
According to a study last year by Demographia, Dhaka in Bangladesh is the world's densest urban area, with 43,500 people per square kilometre.
Cities in Asia dominate the list, with Hyderabad in Pakistan and India's Mumbai completing the top three. Other Indian cities like Surat and Kannur make up 10 of the top 20.
The highest European city in the list is Genoa in Italy at 365th, with 7,900 people per square kilometre. And London? We come in all the way down at 560th.
But Londoners are world class when it comes to complaining about overcrowding.
Mayor Boris Johnson's official housing strategy says London "is growing at a rate not seen since Victorian times." One of the city's busiest Underground stations, Oxford Circus, saw 113 full and partial closures last year.
London is already home to over eight million people, with the population on course to hit 11 million by 2050.