The Saudi prince also owns stakes in Twitter and Lyft , and says Snapchat has only just scratched the surface of its potential.
Saudi Arabia's Prince Alwaleed bin Talal has bought a 2.3% stake in Snap - the company behind Snapchat - for $250m (£193m).
The billionaire, who was held for two months in a high-profile corruption crackdown, said he made the investment on 25 May.
He paid about $11 a share.
His investment comes about three years after he met Snap chief executive Evan Spiegel and chief strategy officer Imran Khan, when the two executives visited Saudi capital Riyadh.
"Snapchat is one of the most innovative social
media platforms in the world and we believe it has only just begun to scratch the surface of its true potential and we are blessed to be part of it," Prince Alwaleed said in a statement.
Alwaleed holds stakes in other tech and social media companies, including Twitter, JD.com and Lyft.
The deal comes as Snap posted second-quarter earnings on Tuesday that showed Snapchat had lost users.
The number of daily active users fell 2% in the latest quarter to 188 million, coming in below Wall Street's expectations of 193 million users.
It is the latest social media company to disappoint investors after Facebook and Twitter also saw a decline in users.