The new option is called UberWav and will be available, the company says, "at the push of a button" at the same cost as cheaper UberX fares.
Recently, Brighton councillors considering whether to grant Uber a licence questioned options for wheelchair users.
Accessibility charities were involved in the new service's development.
Scope, Whizz-Kidz and Transport for All are supporting the launch of UberWav, and Uber says it is investing more than Â£1m over the first 18 months to establish the product.
The vehicles will be equipped with a rear-entry ramp, winch and restraints, allowing wheelchair users to travel with one additional passenger.
An Uber spokesman said the company was initially providing 55 vehicles in the new fleet but planned to expand this to more than 100 "in the coming months".
He added Uber expected wait times of "around 25 minutes" in Zones 1-2 and "40 minutes" in Zones 3-4 during the first few weeks.
"We're proud to be making one of the biggest ever investments in accessible private hire in London and will be working hard to keep waiting times as low as possible as the service expands," said Tom Elvidge, Uber's general manager in London.
The service is "a step in the right direction" according to Ruth Owen, chief executive of Whizz-Kidz.
"This new initiative will give disabled people in London a much-needed additional option for planning their travel across the capital," she added.
In the past, Uber has faced criticism for not offering wheelchair accessible vehicles in more cities.
Recently, the company settled a court case in California after its drivers were accused of turning away passengers with guide dogs.
London is currently the only UK location in which UberWav has been made available.
"London [black] cabs have always been easier to access because of their big doors and the space where seats flap up at the back," said Prof Tony Travers, at the London School of Economics.
"I think Uber in London were under more pressure because their main competitors had an advantage," he told the BBC.
But Uber may soon be met with added scrutiny from London's newly elected Mayor.
Sadiq Khan focused on public transport issues during his campaign - and dealt with the issue of Uber during an LBC radio phone-in.
Mr Khan told a black-cab driver he felt it had been a "mistake" that Transport for London (TfL) had allowed Uber taxis "to come on stream".
A rival, Karhoo, also launched in London this week.
The app allows travellers to compare and book licensed taxis and private hire vehicles - from black cabs to executive cars.
Karhoo has said it will give users access to more than 30,000 vehicles in London.
Passengers will be able to make multiple bookings and be given a final price at the time of booking.
Unlike Uber, there will also be no surge pricing during peak periods.
"Karhoo gives passengers more choice and transparency when booking a cab and, with our ever-growing network of local operators, Karhoo will make it easier to book a ride outside central London than ever before," said Karhoo chief executive and founder Daniel Ishag.
"It's evidence, lest we need it, that Uber really was a positive disruptive element in the market," said Prof Travers.
"It shows how successful market innovation can drive further innovation."

Peter Allott, the 36-year-old deputy head at St Benedict's, has been charged with possessing, showing and making category A indecent images of children.
He is also accused of two counts of possession of extreme pornography, the National Crime Agency said.
He appeared before Ealing magistrates earlier and was remanded in custody.
Mr Allott is next due to appear in court on 23 December at a venue to be confirmed.
St Benedict's is a co-educational school for junior and senior school pupils. Last year 1,092 pupils were registered at the school.
In 2010 Lord Carlile conducted a separate and unrelated inquiry into the "terrible legacy" of 21 cases of historical sex abuse at the school since 1970.
The Independent Schools Inspectorate said in 2014 St Benedict's had a proactive approach to safeguarding which had improved since a previous inspection in 2012.
Uber has launched a fleet of wheelchair-accessible vehicles that can be requested via the app.
[NEXT_CONCEPT]
The deputy head of a fee-paying Catholic school in Ealing has been accused of possessing the most extreme category of indecent child images.