The investment of $2.8 billion over the next 12 years includes Honda paying GM $750 million immediately as it takes a 5.7 percent stake in Cruise Holdings.
General Motors said the Honda investment puts the Cruise valuation at $14.6 billion, or about a third of GM's $48 billion market value. It comes just months after Softbank's Vision Fund invested $2.25 billion in the GM unit.
GM shares jumped as much as 7 percent on the news in premarket trading but by mid-morning the stock was up less than 2 percent. The Detroit automaker's shares are down more than 21 percent over the past year.
Honda's U.S. shares were down more than 3 percent in trading Wednesday.
Together, GM and Honda will develop and build a wide-use autonomous vehicle intended to be deployed worldwide. The vehicle will be manufactured at a General Motors plant, though no date has been set for deployment of the vehicle.