The money will help the ride-hailing service to expand in the Middle East, where the company says 80% of its Saudi Arabian users are women.
Women are banned from driving themselves in the country.
The new funding values Uber at $62.5bn and will put one of the fund's managing directors, Yasir al-Rumayyan, on the board.
The investment from the Public Investment Fund, set up by the kingdom to develop the country and invest its oil revenues, was part of Uber's most recent fundraising round.
Uber will invest $250m in the Middle East, where it has been expanding aggressively.
So-called ride-hailing apps, whereby vetted drivers pick up paying passengers, are expanding rapidly around the world, despite certain cities banning the services amid fears over the standards and licensing of drivers.
The European Commission on Thursday warned against restrictions on "sharing economy" services such as Uber and Airbnb.
"Absolute bans and quantitative restrictions should only be used as a measure of last resort," it said.
Any restrictions by EU members on these online services should be proportionate to the public interest, the Commission added.
Ride-hailing apps have attracted significant cash injections from a range of investors.
Carmakers Toyota and Volkswagen recently struck separate partnerships with Uber and Gett, an Israel-based rideshare operator.
Uber's deal with Toyota followed Apple's $1bn investment in Chinese ride-hailing service Didi Chuxing.
In March, General Motors invested $500m in Lyft, a US rival to Uber, to help develop an on-demand network of self-driving cars.
Uber has attracted a $3.5bn (£2.43bn) investment from Saudi Arabia's Public Investment Fund.