Both companies have confirmed the deal to The New York Times, although details about the scope of the agreement have not yet been revealed.
A Lyft spokeswoman told the newspaper, "Waymo holds today’s best self-driving technology, and collaborating with them will accelerate our shared vision of improving lives with the world’s best transportation".
While a Google spokesman told The New York Times, "Lyft’s vision and commitment to improving the way cities move will help Waymo’s self-driving technology reach more people, in more places".
Google has been working on self-driving car technology for at least eight years. Last year, it renamed its Self-Driving Car Project to Waymo, and gave its leaders the task of bringing the technology to market.
Until recently Google has been testing its software and hardware, on both public and private roads, with a fleet of Lexus RX450h crossovers, which were modified in-house. Last year, it revealed a self-driving version of the Chrysler Pacifica plug-in hybrid co-developed with Fiat Chrysler.
Initially the search giant placed an order for 100 of the hybrid people movers, but added a further 500 cars to the tab late in April 2017 when it announced an 'early rider' trial program for residents of Phoenix, Arizona.
Lyft launched its ride-hailing app in 2012, and is now the second most used service of its kind in the US, a long way behind leader Uber. Unlike its competitor, Lyft has no current plans to develop its own self-driving car technology, instead it has been seeking strategic relationships.
Earlier this year, General Motors invested US$500 million ($662 million) in Lyft and took a seat on its board. Sources informed Reuters in February that Lyft would begin testing a fleet of autonomous Chevrolet Bolt hatchbacks from 2018.
It's unclear at this stage if these existing deals and partnerships will be affected by the new agreement between Waymo and Lyft.