Page and Brin said in a blog post that "it's the natural time to simplify our management structure."
Page became CEO of Alphabet after Google restructured to form the parent company in 2015. He had previously been CEO of Google.
Alphabet CEO Larry Page announced Tuesday that he will step down from the position. Google CEO Sundar Pichai will take over as CEO of the parent company in addition to his current role. Co-founder Sergey Brin will also step down as president of Alphabet and the role will be eliminated.
Alphabet's stock was up as much as 0.8% after hours.
"With Alphabet now well-established, and Google and the Other Bets operating effectively as independent companies, it's the natural time to simplify our management structure," Page and Brin wrote in a blog post announcing the change. "We've never been ones to hold on to management roles when we think there's a better way to run the company. And Alphabet and Google no longer need two CEOs and a President."