His endorsement of the privacy-focussed search tool comes amid criticism of Google’s data gathering practices.
“I love DuckDuckGo,” Mr Dorsey tweeted. “My default search engine for a while now. The app is even better!”
DuckDuckGo responded: “That’s great to hear Jack! Happy to have you on the Duck side.”
Unlike Google, DuckDuckGo refuses to profile its users by collecting data on searches. This means it does not serve targeted ads or personalised search results.