Mr Acton, now the head of non-profit WhatsApp rival Signal, blasted Facebook CEO Mark Zuckerberg for trading privacy for revenue by allowing ads on his platform.
WhatsApp co-founder Brian Acton urged people to 'delete' their Facebook accounts now, during an address made to students.
It comes after the world's largest social network has been beset by a string of privacy scandals.
Mr Acton has been openly critical of Silicon Valley firms like Facebook and Google in the past for their seemingly profit-driven approach at the expense of people's data.
The data of 87 million users was improperly accessed by Cambridge Analytica, linked to the 2016 Trump presidential campaign.
Facebook is also facing a slew of lawsuits and regulatory inquiries over its privacy practices, including ongoing investigations by the U.S. Federal Trade Commission, the Securities and Exchange Commission and two state agencies in New York.
It is the second time that Mr Acton has made the comment publicly. Last year he posted on Twitter 'It is time. #delete facebook' following Facebook's failings involving a political consultancy firm.
In 2014, Acton sold the instant messaging service to Mark Zuckerberg for $19 billion (£15bn) and left in 2017 over its plans to introduce ads to the app.
Mr Acton defended his decision to sell saying that he wanted his employees and investors to profit and he didn't have the power, or 'clout' to say no.